ARS

What ARS does

ARS Co., Ltd. (アルス株式会社) is a privately held Japanese semiconductor back-end manufacturer and electronics manufacturing services (EMS) provider headquartered in Motomiya City, Fukushima Prefecture, with approximately 450 employees as of January 2026 and JPY 98 million in stated capital. Founded in 1972 and tracing its origins to telecommunications crossbar switch assembly, ARS has evolved through a series of mergers and renamings into a multi-pillar contract manufacturer whose five integrated business lines cover wafer testing and laser trimming (100-300mm wafer sizes, mixed SoC and analog testers from Advantest, ShibaSoku, and SPANDNIX), standard and custom semiconductor package assembly (USB-A/B, QFN, SOP/TSSOP, plus custom sensor, communication, and power modules), EMS PCB assembly (11 SMT lines supporting up to 510x460mm boards with 3D AOI, X-ray, FCT/ICT, and cleanroom Class 1,000 environments), power supply development and manufacturing (approximately 1,000 standard AC/DC and DC/DC models across the KH, APF, ES, KM, TG, and related series plus 500+ custom and 1,500+ semi-custom design track records), and — added in January 2026 via a business succession from Toyo Electronic Industry — embedded system software and hardware development anchored by an Embedded System Center in Niigata. ARS generates revenue through project-based contract manufacturing services (wafer test, package assembly, EMS, prototyping, and reliability/failure analysis) plus hardware sales of its standard and custom power-supply catalog, distributed through authorized dealers (Kato Tek, MEP, Crown Musen, Daitron, Takebishi, Toyokizai). Its go-to-market is consultative, direct enterprise sales via the corporate website and a Tokyo Satellite Office, and its end customers span industrial equipment, automotive, medical devices, telecommunications, consumer products, amusement, and railway/infrastructure. ARS also operates a manufacturing-outsourcing and worker-dispatch arm and runs a workforce dispatching license under Ministry of Health, Labour and Welfare registration. Quality and regulatory credentials include ISO 9001 (since 2002), ISO 14001 (since 2001), ISO 13485 (since 2019), IATF 16949 (since 2018), ANSI ESD S20.20 (since 2014), and RCJS-5-1/IECQ ESD (since 2025), plus a Fukushima Prefecture Medical Device Manufacturing License — collectively positioning the firm for regulated-industry contracts that competitors without these credentials cannot pursue. Leadership rests with President and CEO Tsutomu Ouchi, and the business remains independent with no identified parent or external private-equity ownership.

Name

ARS

Legal name

ARS Co., Ltd.

Website

https://arusu.co.jp

Company type

Private

Founded year

1972

Operating status

Operating

Headcount range

251–500 employees

Short description

ARS Co., Ltd. is a privately held Japanese semiconductor back-end manufacturer and EMS provider offering integrated wafer testing, semiconductor packaging, PCB assembly, custom power supply development, and embedded system services. It serves automotive, medical, industrial, telecom, consumer, amusement, and rail end-markets from eight factories in Fukushima plus Tokyo and Niigata sites.

Ownership category

akta.pro rank

Product category

Semiconductor Back-End Manufacturing and Contract Electronics Manufacturing

NAICS

Semiconductor and Other Electronic Component Manufacturing (33441), Other Measuring and Controlling Device Manufacturing (334519), Navigational, Measuring, Electromedical, and Control Instruments Manufacturing (33451)

SIC

Industrial Instruments For Measurement, Display, And Control (3823), Electrical Industrial Apparatus (3620), Instruments For Meas & Testing Of Electricity & Elec Signals (3825)

akta.pro primary industry

Industrial Electronics Manufacturing Services (EMS) (IMAGAGAA)

akta.pro secondary industries

Assembly & Packaging Services (Wirebond/Flip-Chip/FCBGA) (HDAHADAA), Test, Probe & Burn-In Equipment (Wafer Sort/Final Test) (HDAHAEAJ), Ruggedized/Harsh-Environment Electronics Manufacturing (IP-rated, shock/vibration, wide-temp) (IMAGAGAF)

Keywords

• Semiconductor back-end manufacturing
• Electronics manufacturing services
• Switching power supply design
• Wafer testing services
• Embedded system development

Headquarters

HQ city

Motomiya

HQ country

Japan

HQ region

Asia

Offices5 records

Markets served

GTM type

B2B

Offering type

Services

Cost components

Personnel, Operations, Technology or R&D, Supply Chain, Infrastructure, Marketing or Sales, Others

Revenue model

1. Semiconductor Back-End Manufacturing: Contract manufacturing covering wafer testing (electrical testing and laser trimming), semiconductor package assembly (standard and custom), SMD PCB assembly, and electronic device assembly. Revenue is generated through project-based and recurring manufacturing contracts with customers across industrial, automotive, medical, and communications sectors. Includes one-stop domestic production from prototyping through mass production.
2. Power Supply Development & Manufacturing: Development, manufacturing, and sales of switching power supplies, hybrid ICs, and custom power solutions. Approximately 1,000 standard models (AC/DC converters and DC/DC converters) and custom/semi-custom development services. Revenue includes product sales and design/development fees. The company also inherited the 'EATER' (イーター) brand from Eater Electric Industry.
3. Embedded System Development: Microcontroller-based embedded software and hardware design services, including FPGA design, PC/tablet software, and test automation systems using LabVIEW. Revenue is generated through contract development projects, particularly following the succession of Toyo Electronic Industry's system development business.
4. Manufacturing Outsourcing / Workforce Services: Outsourcing of standardized, non-core manufacturing operations including material procurement, production, distribution processing, and inspection. Also includes workforce outsourcing of operators and engineers and business systems development. Certified under medical device manufacturing, IATF 16949, ISO 13485, and RCJS-5-1 standards.

Pricing tiers

Go-to-market motion1 record

Distribution channels3 records

Marketing channels4 records

Core offering

ARS Co., Ltd. is a Japanese contract manufacturer providing one-stop, domestically integrated services spanning semiconductor back-end manufacturing (wafer testing with laser trimming, standard and custom semiconductor package assembly, and EMS PCB assembly across 11 SMT lines), switching power supply design and manufacturing (approximately 1,000 standard AC/DC and DC/DC converter models plus 500+ custom and 1,500+ semi-custom designs), and microcontroller-based embedded system development. Operations are delivered from eight factories in Motomiya City, Fukushima Prefecture, supported by reliability testing and prototyping services and certified to IATF 16949, ISO 13485, ISO 9001, ISO 14001, ANSI ESD S20.20, and RCJS-5-1 standards.

Product overview

ARS provides one-stop semiconductor, EMS, and power development solutions through six integrated business divisions: (1) Wafer Testing & Laser Trimming - electrical testing and trimming services for 100-300mm wafers; (2) Semiconductor Package Assembly - standard packages (USB-A/B/C, LNC, QFN, SOP, TSSOP, SOT) and custom modules (sensor/communication, power modules/PMIC, ultra-compact packages); (3) EMS - SMT assembly with 11 lines supporting PCB sizes up to 510x460mm, including testing and product assembly; (4) Power Supplies - approximately 1,000 standard models including AC/DC converters (KH, APF, ES, PL, SV, VT, WR, ER, KG/KL, BJ, OJ, OB, KM series) and DC/DC converters (TG, VT, SV, NV, OG, OC, OE, OB series); (5) Embedded System Development - software and hardware development including FPGA design; (6) Prototyping & Manufacturing Outsourcing - from prototype to mass production support. The portfolio is tied together through integrated quality management and traceability systems.

Differentiator

Problem solved

Functional benefit

Products and services

• Wafer Testing & Laser Trimming Service Contract electrical testing for wafers from 100mm to 300mm, supporting Logic, Mixed-Signal, and Analog devices, including laser trimming services with ESI equipment for 4-8 inch wafers and operating temperatures from -55°C to 200°C. Targeted at semiconductor OEMs and fabless customers needing back-end test capability.
• Standard Semiconductor Packages (USB-A, USB-B, QFN, SOP/TSSOP, SOT, LNC) Catalogue of standard non-leaded and leaded semiconductor packages—including ultra-small board non-leaded USB-A (4–12 pin), USB-B (3–12 pin), QFN (6–16 pin), SOP/TSSOP (8–24 pin), SOT, and LNC packages—manufactured with glass epoxy substrates, Cu frame substrates, or nickel electroformed transfer leads. Sold to semiconductor and electronics OEMs needing qualified off-the-shelf package outlines.
• Custom Sensor, Communication, and Power Modules Bespoke semiconductor packages and modules for sensing devices, optical communication devices (hollow, exposed, MCM, and stack processes), and power modules/PMICs (IGBT + control IC + wire bonding + resin encapsulation). Configurable as PCB modules, PCB+frame modules, or frame modules. Targeted at customers with application-specific packaging needs.
• EMS (Electronics Manufacturing Services) One-stop domestic electronics manufacturing covering SMT assembly across 11 lines, PCB assembly, finished-product assembly, and testing for designs up to 510mm × 460mm. Includes bare-chip mounting in cleanrooms, 3D AOI, X-ray inspection, FCT/ICT, and selective soldering. Sold to OEMs across industrial, automotive, medical, telecommunications, consumer, and amusement sectors.
• KH / KHS Series AC/DC Power Supplies Chassis/case-type AC/DC switching power supplies with AC100–200V input and 300/500W output capacity, achieving up to 94% efficiency with a 43% size reduction vs. prior models. KHS300 supports 500W peak output. Sold to industrial equipment, automation, and embedded system OEMs.
• APF Series High-Power AC/DC Power Supplies High-power AC/DC converter series delivering 3,000W output from single-phase or three-phase inputs, configurable up to 9kW through internal parallel operation, with 93% efficiency. Targeted at industrial and high-power equipment OEMs.
• ES Series High-Efficiency AC/DC Power Supplies Case-type AC/DC switching converters with universal AC input across 15/30/50/75/100/150W capacities and up to 90.5% efficiency. Sold to industrial, embedded, and commercial equipment OEMs.
• TGS150/TG Series Railway-Grade DC/DC Converters DC/DC converters for railway and industrial equipment with 150W output, DC110V input (DC60–145V range), wide operating temperature range, 10-year expected lifetime, and IEC 61373 / JIS E4031 Category 1 Class B compliance. Targeted at railway equipment manufacturers and rugged industrial systems integrators.
• KM Series Medical-Grade AC/DC Power Supplies Board-type medical AC/DC converters certified to IEC 60601-1, delivering 300W output with insulation Class II (double insulation) and MOPP-compliant design, UL and CE certified. Targeted at medical device manufacturers needing compliant internal power conversion.
• Reliability Testing and Failure Analysis Service Comprehensive reliability and failure-analysis services including environmental stress tests (THB, HAST, temperature cycling), accelerated life testing (HTOL), package assembly integrity tests, and semiconductor analysis (X-ray, SAT, decapsulation, cross-section, FTIR, SEM/TEM/STEM with EDS/EPMA, IR-OBIRCH, emission microscopy). Tests conducted under JESD22, JEITA, and AEC-Q100 standards. Sold to automotive, medical, and industrial OEMs requiring qualification evidence.
• Prototyping Service Comprehensive prototype support covering R&D exploratory prototyping (free-form, spot work, IC/MEMS evaluation, materials evaluation, defect analysis) and mass-production-ready prototyping (standard/custom packages, modules, single-process support, 1,000+ unit lots) using production equipment for condition selection and margin evaluation. Sold to development teams that need agile bridging between R&D and mass production.
• Embedded System Development Service Manufacturing-integrated embedded system development covering software (embedded, PC, tablet) and hardware (digital/analog circuit, FPGA), including RTL design in VHDL and Verilog-HDL with simulation verification. Supports μITRON, VxWorks, FreeRTOS, and Arduino embedded OS as well as LabVIEW-based test/control systems. Sold to industrial, telecommunications, IoT, and infrastructure monitoring OEMs.
• Manufacturing Outsourcing / Workforce Services Outsourcing of non-core manufacturing operations including material procurement, production, distribution processing, and inspection, plus operator and engineer workforce dispatch and business systems development. Supports high-mix, low-volume production with ESD countermeasures and cleanroom facilities under a Worker Dispatching Business License (Haken 07-300602). Targeted at OEMs seeking a flexible, certified production partner.
• Custom Power Supply Design and Manufacturing Bespoke design and manufacturing of switching power supplies and hybrid ICs with a track record of 500+ custom and 1,500+ semi-custom power supply designs (alongside approximately 1,000 standard models). Includes analog power technology inherited from the Eater (イーター) brand of Eater Electric Industry. Targeted at OEMs with application-specific power conversion needs.

Quantifiable outcome

• High-efficiency power supply achieving up to 94% efficiency (KH/KHS series, AC200Vin)
• +6 more outcomes

Segments7 records

Ideal customer profiles6 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature7 records

Partnerships

Three partnerships are on record, tiered core and minor.

• Toyo Electronic Industry Co., Ltd. (東洋電子工業株式会社)coreStrategic or Co-development Partner · 1 January 2026ARS succeeded to the system development business of Toyo Electronic Industry Co., Ltd. in January 2026. This succession established ARS's Embedded System Center in Niigata, inheriting Toyo Electronic Industry's embedded software and hardware design expertise and extensive track record.
• Clareus Co., Ltd. (クレアース株式会社)minorOthers · 1 January 2026Established as part of the business succession from Toyo Electronic Industry in January 2026. Clareus Co., Ltd. was incorporated as a new subsidiary to facilitate the transition of the inherited system development business.
• Fukushima Firebonds (福島ファイヤーボンズ)minorGTM or Marketing Partner · 1 October 2025ARS concluded an official partnership agreement with Fukushima Firebonds, a professional basketball team competing in B.LEAGUE, for the 2025-26 season. The partnership reflects ARS's commitment to regional community engagement and shared values of challenging spirit and regional revitalization.

Scale indicators7 records

Recent moves10 records

Expansion highlights6 records

Market position

Competitive moat4 records

Key highlights7 records

Customer concentration

Compliance7 records

Revenue estimate

Valuation estimate

Number of profiles

Profiles1 record

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about ARS