What Fuji Seiko does

Fuji Seiko (富士精工株式会社, Fuji Bellows Co., Ltd.) is a privately held Japanese precision-manufacturing company founded on May 15, 1947, in Fuji City, Shizuoka Prefecture, and now headquartered in Ayase, Kanagawa Prefecture. The company designs, manufactures, and sells engineered components for temperature, pressure, and fluid control, organized into three business divisions: Automotive (thermostats, BAK bi-actuating thermostats, integrated plastic-case thermostat modules, thermo valves for AT/CVT transmissions, wax-element thermo switches, bellows-type pressure switches, and pressure relief valves), Housing Equipment (constant-flow valves, patented micro constant-flow valves, PTC/wax-element thermal valves for floor heating and bath reheat, and integrated complex-function valves), and Aerospace/Industrial Bellows (formed and assembled bellows, rocket bellows, aircraft bellows, and Inconel 625/718 bellows for cryogenic-to-800°C+ and high-pressure-hydrogen service).

Its core technology platform rests on two proprietary foundations: (1) the wax-element (thermo pellet) temperature-actuation technology that converts wax volumetric change into mechanical output across a -40°C to 130°C/150°C range, and (2) metal bellows forming and precision welding technology built up over 75+ years and applied to stainless and nickel-alloy tubes for sensors, shaft seals, expansion joints, and rocket/aerospace assemblies. The company operates five Japan facilities (Ayase HQ/Plant, Sales & Technology Center in Ayase, Sagami Plant in Yamato, Tsukuba Plant in Kasumigaura, Fuji Plant in Shizuoka) plus a 100%-owned manufacturing subsidiary, Fuji Seiko Vietnam Co., Ltd., in Nomura-Hai Phong Industrial Zone, Vietnam (established 2011, relocated 2017).

Fuji Seiko's commercial model is direct B2B sales of designed-in OEM components on a quote-based, negotiated pricing structure to major enterprise customers across automotive (Toyota, Honda, Nissan, Mazda, Suzuki, GM, Volvo), automotive Tier-1 (Denso, Keihin, T.RAD, Tokyo Roki, Hitachi Automotive Systems), housing equipment (TOTO, LIXIL, Noritz, Panasonic), industrial machinery (Komatsu, Kawasaki Heavy Industries, Mitsubishi Heavy Industries, Kobe Steel), and aerospace/defense (IHI, IHI Aerospace, Toshiba, Yokogawa Electric, JEOL, the Japan Ministry of Defense). The company is certified to ISO 9001 (Automotive and Housing divisions), JIS Q 9100 (Aerospace division), and ISO 14001, and it has supplied bellows into JAXA's domestic rocket programs from the N-rocket through the H3. Control rests with the Ando family, with Jun Ando assuming the presidency from Hideo Ando on May 27, 2025.

Name

Fuji Seiko

Legal name

富士精工株式会社 (Fuji Bellows Co., Ltd.)

Website

https://fuji-seiko.co.jp

Company type

Private

Founded year

1947

Operating status

Operating

Headcount range

251–500 employees

Short description

Fuji Seiko is a Japanese precision manufacturer (founded 1947, 260 employees) that designs, produces, and sells thermostats, wax-element valves, constant-flow valves, and metal bellows assemblies to automotive, housing-equipment, and aerospace OEMs including Toyota, TOTO, LIXIL, and IHI.

Ownership category

akta.pro rank

Product category

Precision Engineered Components

NAICS

Relay and Industrial Control Manufacturing (335314), Instruments and Related Products Manufacturing for Measuring, Displaying, and Controlling Industrial Process Variables (334513), Speed Changer, Industrial High-Speed Drive, and Gear Manufacturing (333612)

SIC

Screw Machine Products (3451), Electrical Industrial Apparatus (3620), Aircraft Engines & Engine Parts (3724), Industrial Instruments For Measurement, Display, And Control (3823)

akta.pro primary industry

Aerospace Seals, Gaskets, O-Rings & Elastomeric Components (IMABANAF)

akta.pro secondary industries

Aerospace Fuel System Components (Tanks, Lines, Valves) (IMABANAJ), Electromechanical Components (Relays, Switches, Potentiometers, Encoders) (IMAGAJAB), Refrigeration Components & Controls (Compressors, Valves, Sensors) (IMAHAKAH)

Keywords

• Precision industrial components
• Thermal control devices
• Automotive OEM parts
• Fluid control valves
• Pressure switch manufacturing

Headquarters

HQ city

Ayase

HQ country

Japan

HQ region

Asia

Offices6 records

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

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

Revenue model

1. Component Sales (Automotive, Housing, Aerospace): Design, manufacture, and sale of engineered components — thermostats, wax elements, thermo valves, pressure switches, constant-flow valves, bellows and bellows assemblies — sold to industrial OEM customers. Revenue is generated through direct B2B sales of manufactured parts on a project/spec basis under long-term customer relationships (e.g., Toyota, Honda, Nissan, TOTO, LIXIL, IHI, Mitsubishi Heavy Industries).
2. Design-to-Specification Engineering & Custom Assembly: Integrated design, manufacturing, and sales services for application-specific components (e.g., integrated thermostat modules, custom bellows assemblies for rocket valves, composite-function valves combining constant-flow and on/off valves). Captured within the same hardware sales stream but with design engineering value-add.

Pricing tiers

Go-to-market motion3 records

Distribution channels3 records

Marketing channels5 records

Core offering

Fuji Seiko designs, manufactures, and markets precision components including thermostats, bellows, wax elements, constant-flow valves, and pressure switches for the automotive, housing equipment, and aerospace sectors. The company supplies critical thermal regulation and fluid control parts used by OEMs in demanding industrial applications.

Product overview

Fuji Seiko (Fuji Bellows Co., Ltd.) is a single, integrated precision-manufacturing company — not a software platform — that designs, manufactures and sells three product groups under one corporate umbrella: (1) Automotive components such as Thermostats (including BAK Thermostat, Integrated Thermostat with Plastic Case, Top/Side/Inline/Bottom Bypass types), Thermo Valves (incl. AT/CVT), the underlying Wax Element (Thermo Pellet) and its derivative Wax Element Type Thermo Switch, Bellows-type Pressure Switches and Pressure Relief Valves; (2) Housing-equipment components such as the Constant Flow Valve (Spring and Diaphragm types), the Micro Constant Flow Valve, the Thermal Valve for floor heating and bath reheat, and the Complex Function Valve (High Efficiency Valve); and (3) Aerospace / industrial Bellows and Bellows assemblies, including Formed Bellows, Rocket Bellows, Aircraft Bellows, and Inconel (625 / 718) Bellows. The wax-pellet and bellows technologies are the foundational platforms that span all three business units, with each unit (Ayase for automotive, Sagami for aerospace, Tsukuba for housing equipment, plus Fuji plant and overseas subsidiary Fuji Seiko Vietnam) operating as a specialized production arm of the unified Fuji Seiko portfolio.

Differentiator

Problem solved

Functional benefit

Products and services

• Thermostats Precision thermostats designed for thermal regulation in automotive, housing equipment, and aerospace applications, supplied to OEM manufacturers.
• Bellows Precision metal bellows used as mechanical elements in thermal and fluid control assemblies supplied to industrial OEMs.
• Wax elements Wax-based thermal actuator elements used in temperature-responsive control applications for industrial OEM customers.
• Constant-flow valves Precision constant-flow valves designed to regulate fluid flow in automotive, housing equipment, and aerospace systems supplied to OEM manufacturers.
• Pressure switches Pressure switches designed to monitor and respond to pressure thresholds in industrial OEM applications across automotive, housing equipment, and aerospace sectors.

Quantifiable outcome

• Wide temperature control range from -40°C to 130°C (wax element / thermo pellet) for automotive thermostats and switches
• +4 more outcomes

Named customers35 records

Segments4 records

Ideal customer profiles1 record

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature9 records

Partnerships

Three partnerships are on record, tiered core / flagship and historical (no longer active).

• JAXA (Japan Aerospace Exploration Agency) — H3 Rocket Programcore / flagshipGTM or Marketing Partner · 1 January 2025Fuji Seiko is publicly listed as a "supporter" of the JAXA H3 rocket program, with homepage banners ("富士精工はH3ロケットを応援します") linking to JAXA's official supporter page and countdown page. The company has supplied bellows for fuel piping, actuators, fuel control valves, and other valves on domestic rockets from the N-rocket through H3.
• Fuji Seiko Vietnam Co., Ltd.core / flagshipStrategic or Co-development Partner · 1 January 2011100%-owned overseas manufacturing subsidiary established in 2011 at Nomura Industrial Park, Hai Phong City, Vietnam; relocated within the same industrial estate in 2017. Operates as the company's global production and cost-optimization base, supporting supply to worldwide OEM customers from a Vietnamese footprint.
• Stant Thomson (米国スタンダード・トムソン社)historical (no longer active)Strategic or Co-development Partner · 1 January 1963In 1963, Fuji Seiko entered a joint venture with U.S. firm Standard Thomson to establish Fuji Thomson Co., Ltd. (富士トムソン株式会社) to manufacture wax-type thermostats at scale. The Ayase plant (then Fuji Thomson Plant) was established in 1969 for that purpose. The joint venture ended in 1999 with the merger of three group companies (Fuji Bellows, Fuji-Thomson, Fuji-Seiki) into the current Fuji Bellows Co., Ltd.

Scale indicators7 records

Recent moves7 records

Expansion highlights6 records

Broad incumbents

• Mahle GmbH: German global Tier-1 supplier of powertrain and thermal management components, including automotive thermostats and engine cooling modules. Competes with Fuji Seiko on OEM thermostat and thermal management design-ins but operates a much broader portfolio at significantly larger scale.
• Hanon Systems: South Korea-headquartered global thermal management Tier-1 supplier (formerly Halla Visteon Climate Control). Broad incumbent competing with Fuji Seiko on vehicle thermal management content, with substantially greater scale and an EV-focused product roadmap.

Direct peers

• Vernet SA: France-based global specialist in automotive thermostats, thermal management valves, and wax elements. Closest international analog to Fuji Seiko's automotive thermostat and wax-element platform, competing for the same global OEM thermostat sockets.
• T.RAD Co., Ltd. Japanese manufacturer of automotive radiators, heat exchangers, and thermostat-related thermal management components. Listed among Fuji Seiko's Tier-1 customer set but also a direct competitor in thermostat and cooling module supply.
• Keihin Corporation (Hitachi Astemo): Japanese automotive thermal and fluid management component supplier (now part of Hitachi Astemo), also a Fuji Seiko customer in the data. Overlaps with Fuji Seiko's thermo valve and constant-flow control product lines for ICE and motorcycle applications.
• Stant (Standard Motor Products): U.S. heritage thermostat and cooling-system component brand, originally part of Standard-Thomson — Fuji Seiko's former 1963–1999 JV partner. Closest Western thermostat peer in technology lineage and product category, now part of Standard Motor Products.
• Nippon Thermostat Co., Ltd. Japanese specialist manufacturer of automotive thermostats, temperature-control valves, and wax elements. Direct head-to-head peer in the ICE thermostat and wax-pellet business, serving overlapping Japanese OEMs on similar product categories.
• Witzenmann GmbH: Germany-based global specialist in metal bellows, expansion joints, and flexible metallic elements for aerospace, nuclear, and industrial applications. Closest direct analog to Fuji Seiko's Inconel bellows and aerospace/sealing business, serving similar extreme-environment OEM customers.

Others

• IHI Corporation: Major Japanese aerospace and heavy-industry prime contractor and a current Fuji Seiko customer. Acts as both a buyer (for rocket/aerospace bellows) and adjacent system integrator in space launch, providing a downstream demand signal for Fuji Seiko's aerospace business.

Regional players

• CKD Corporation: Japanese manufacturer of pneumatic, fluid control, and automation components including specialized valves. Comparable Japanese precision fluid-control peer serving industrial OEMs in overlapping domestic end markets.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat4 records

Key risks7 records

Key highlights7 records

Customer concentration

Compliance3 records

Revenue estimate

Valuation estimate

Number of profiles

Subsidiaries1 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 Fuji Seiko