Mitsui Seiki

What Mitsui Seiki does

Mitsui Seiki Kogyo Co., Ltd. (三井精機工業株式会社) is a privately held Japanese manufacturer founded in 1928 and headquartered in Kawaguchi, Saitama Prefecture, operating with 501-1000 employees. The company operates two core product lines built around complementary precision-engineering competencies. The first is high-precision machine tools, including 5-axis vertical machining centers (the Vertex series, which received the 36th Machine Industry Design Award / Japan Brand Award), horizontal machining centers, jig borers, jig grinders, and thread grinding machines — with the latter holding a near-100% domestic market share in Japan's precision ball screw grinding segment. The second is industrial air compressors, differentiated by the proprietary Z-screw compression mechanism, deployed across water-lubricated oil-free series (i-14000 X, U-14000, ZU-Quatro, ZU), oil-lubricated series (Zgaiard X3/X4), scroll compressors (Escal, D-escal), and outdoor-rated units (Zgaiard SKY). Sub-micron machining accuracy is achieved through hand-scraping (kissage) assembly techniques performed in temperature-controlled facilities.

The company's revenue model is anchored on direct enterprise sales of capital equipment with quote-based, multi-year-contract pricing, supplemented by recurring service revenue from an extensive after-sales infrastructure. Mitsui Seiki operates 121 authorized service factories covering all 47 Japanese prefectures, supporting installation, maintenance, repair, and add-on systems such as the Z-Cloud remote monitoring platform, Red-CX multi-compressor controller (up to 8 units), and Z-Mate II PC monitoring (up to 50 compressors). The go-to-market motion is enterprise field sales with website-driven inquiries and trade-show lead generation at events such as Japan PACK, Mechatronics Japan (MECT), and the company's own MTF technical fairs. Customer segments are diversified across precision mold manufacturers, optical component producers, aerospace/aircraft parts manufacturers, and large-scale industrial plants requiring clean compressed air. Geographic reach is almost entirely domestic Japan, with no disclosed international operations, M&A, or funding activity in the available data.

Name

Mitsui Seiki

Legal name

三井精機工業株式会社

Website

https://mitsuiseiki.co.jp

Company type

Private

Founded year

1928

Operating status

Operating

Headcount range

501–1,000 employees

Short description

Mitsui Seiki Kogyo Co., Ltd. (三井精機工業株式会社) is a 1928-founded Japanese manufacturer of sub-micron precision machine tools and proprietary Z-screw industrial compressors, serving enterprise customers in precision molds, optics, aerospace, and large-scale plants across Japan via direct sales and a 121-point service network.

Ownership category

akta.pro rank

Product category

Precision Machine Tools and Industrial Air Compressors

NAICS

Other General Purpose Machinery Manufacturing (3339), Pump and Compressor Manufacturing (33391)

SIC

Machine Tools, Metal Cutting Types (3541), General Industrial Machinery & Equipment (3560)

akta.pro primary industry

Motion & Machine Control (CNC, Robotics Controllers, Servo/Motion Controllers) (IMAGABAG)

akta.pro secondary industry

Pump & Compressor Packages (Skids, Booster Sets) (IMAHANAG)

Keywords

• Precision machining centers
• Industrial air compressors
• Five-axis CNC machines
• Oil-free screw compressors
• Thread grinding machines

Headquarters

HQ city

Saitama

HQ country

Japan

HQ region

Asia

Offices1 record

Markets served

GTM type

B2B

Offering type

Hardware or Manufacturing

Cost components

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

Revenue model

1. Precision Machining Equipment Sales: Sale of high-precision CNC machining centers including 5-axis vertical machining centers (Vertex series), jig grinding machines, and thread grinding machines. One-time capital equipment sales with potential for spare parts and upgrades.
2. Industrial Compressor Sales and Service: Sale of water-lubricated oil-free screw compressors (Z-Cloud and Z-Mate series) along with associated maintenance, repair, and after-market services through their nationwide service network.
3. Technical Services and Maintenance: Comprehensive after-sales technical support, maintenance, and repair services provided through 121 authorized service factories across all 47 Japanese prefectures.

Pricing tiers

Go-to-market motion1 record

Distribution channels2 records

Marketing channels3 records

Core offering

Mitsui Seiki manufactures two core product lines: high-precision machine tools (5-axis vertical machining centers, horizontal machining centers, jig borers, jig grinders, and thread grinding machines) and industrial air compressors built around its proprietary Z-screw water-lubricated oil-free compression mechanism. The company sells these as customized capital equipment to industrial manufacturers in Japan, supported by 121 authorized service factories covering all 47 Japanese prefectures for installation, maintenance, and after-sales support.

Product overview

Mitsui Seiki (三井精機工業株式会社) manufactures two core product lines: high-precision machine tools and industrial air compressors. The machine tool portfolio includes 5-axis vertical machining centers (Vertex series), horizontal machining centers (4-axis and 5-axis configurations), jig borers, jig grinders, and thread grinding machines (with near-100% domestic market share for precision ball screw grinding). The compressor portfolio centers on the proprietary Z-screw compression technology across water-lubricated oil-free series (i-14000 X, U-14000, ZU-Quatro, ZU) and oil-lubricated series (Zgaiard X/Zgaiard), complemented by scroll compressors (Escal, D-escal) and outdoor-rated models (Zgaiard SKY). Supporting offerings include Z-Cloud cloud monitoring, Red-CX multi-compressor control, Z-Mate II PC monitoring, clean air filtration systems, and receiver tanks. The company operates 121 designated service factories across Japan's 47 prefectures.

Differentiator

Problem solved

Functional benefit

Products and services

• Machine Tools (工作機械) High-precision CNC machining centers including 5-axis and vertical/horizontal configurations, jig borers, jig grinders, and thread grinding machines manufactured in temperature-controlled facilities using hand-scraping techniques to achieve sub-micron precision. The line serves precision mold manufacturers, optical component producers, and aerospace parts manufacturers in Japan.
• Industrial Compressors (コンプレッサ) Industrial air compressors including water-lubricated oil-free screw compressors, oil-lubricated screw compressors, and scroll compressors. Built around the proprietary Z-screw compression mechanism, the lineup serves large-scale factories and industrial plants needing clean, oil-free compressed air.
• Vertex Series (5-axis vertical machining center) 5-axis vertical machining center with cube-on structure achieving jig borer-level precision. Compact footprint (2m x 3m) with up to 500mm diameter workpiece capacity, built-in tilt/rotary table, thermal displacement compensation, and 0.1 micron minimum feed. Targets mold, optical, and aerospace precision component manufacturers.
• Horizontal Machining Centers (横形マシニングセンタ) Horizontal machining centers in 4-axis and 5-axis configurations including trunnion type, table-on-table type, and spindle-tilt type. Pallet sizes range from compact 500mm to large 2500mm workpiece capacity machines for heavy industrial precision manufacturing.
• Vertical Machining Centers (立形マシニングセンタ) Vertical machining centers including 3-axis and 5-axis configurations, precision centers with linear motors, and profile centers for high-precision machining applications.
• Jig Borers (ジグボーラー) Ultra-precision jig borers considered the ultimate mother machine for machining centers, achieving micron-level accuracy through rigorous craftsmanship. Available in traditional and large types up to 3m stroke for high-precision reference and master component manufacturing.
• Thread Grinding Machines (ねじ研削盤) Thread grinding machines for precision ball screw grinding with near-100% domestic market share in Japan. Includes male thread, female thread, and heavy-duty grinding types with various grinding lengths for ball screw production.
• i-14000 X Series (Water-lubricated oil-free inverter compressor) Water-lubricated oil-free inverter screw compressor with Z-screw technology achieving up to 7% increase in discharge air volume. Features SUS rotor for high durability and wear resistance. Power range 15-220kW for industrial plants and large factories.
• U-14000 Series (Water-lubricated oil-free standard compressor) Standard water-lubricated oil-free screw compressor with IE3 premium efficiency motor compliant with Top Runner regulations. Power range 15-75kW for industrial compressed air applications requiring clean, oil-free air.
• ZU-Quatro Series (Compact water-lubricated oil-free compressor) Compact water-lubricated oil-free screw compressor delivering one rank up air volume in its horsepower class. Power range 7.5-11kW for smaller industrial applications needing oil-free compressed air.
• ZU Series (Large-scale water-lubricated oil-free compressor) Large-scale water-lubricated oil-free screw compressor for plants and large factories with top-class discharge volume in same horsepower class. Power range 100-120kW.
• Zgaiard X3 Series (Oil-lubricated screw compressor) Oil-lubricated screw compressor with Z-screw technology available in inverter and constant-speed variants. Features Top Runner regulation compliance, 50°C ambient operation capability, and up to 10% increased discharge air volume. Power range 22-150kW.
• Zgaiard X4 Series (Oil-lubricated screw compressor) Oil-lubricated screw compressor series featuring Modbus communication, browser-based monitoring, Wi-Fi connectivity, and multi-drop control for up to 6 compressors. Designed for ambient temperature 50°C operation with emergency stop button standard on all models.
• Escal Series (Scroll compressor) Environment and energy-saving focused scroll compressor with smooth rotation for efficient power, automatic start-stop system with energy-saving unloader. Power range 3.7-5.5kW for smaller industrial and workshop applications.
• D-escal Series (Oil-free scroll compressor) Oil-free scroll compressor using no oil at all, delivering clean air. Features automatic start-stop system for intermittent operation energy savings. Power range 3.7-7.4kW for applications requiring clean compressed air.
• Zgaiard SKY Series (Outdoor compressor) Outdoor-rated screw compressor with IP23 waterproof protection, compact and powerful design for outdoor installation. Features rain-resistant louvers and waterproof connectors for outdoor deployment in industrial facilities.

Quantifiable outcome

• Dominant near-100% market share in Japan's precision ball screw grinding machine market
• +1 more outcomes

Named customers4 records

Segments4 records

Ideal customer profiles4 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

Feature4 records

Scale indicators3 records

Recent moves5 records

Expansion highlights5 records

Direct peers

• Yamazaki Mazak: Japan's largest machine tool maker and Mitsui Seiki's closest direct competitor in 5-axis vertical machining centers and complex CNC machining. Both serve precision mold, aerospace, and optical manufacturers with high-end multi-axis solutions, though Mazak operates at significantly larger scale globally.
• DMG MORI: Global leader in 5-axis CNC machining centers and turnkey machining solutions, formed through merger of Japan's Mori Seiki and Germany's Gildemeister. Directly competitive with Mitsui Seiki's Vertex and horizontal machining center product lines for precision mold and aerospace customers.
• Makino Milling Machine: Japanese precision machine tool maker specializing in vertical machining centers, horizontal machining centers, and EDM. Competes head-to-head with Mitsui Seiki in aerospace, mold, and high-precision die/mold applications requiring micron-level accuracy.
• Okuma Corporation: Japanese CNC machine tool manufacturer producing machining centers, lathes, and multi-axis machines with proprietary OSP control. Direct competitor to Mitsui Seiki in the domestic precision machining center market for factory automation customers.
• Shibaura Machine (formerly Toshiba Machine): Japanese manufacturer of machine tools (machining centers, lathes), injection molding machines, and industrial equipment. Overlaps with Mitsui Seiki on CNC machining centers and shares Japanese precision manufacturing customer base including semiconductor and automotive.
• Nakamura-Tome Precision Industry: Japanese precision turning and machining center maker (multi-axis lathes, multitasking machines). Direct competitor in mid-sized precision machine tool segment serving aerospace and mold industries, with comparable mid-market scale.
• Yasda Precision Tools: Japanese specialist in precision jig grinding and ultra-precision machining centers, similar heritage to Mitsui Seiki in sub-micron craftsmanship. Most directly comparable in terms of niche precision positioning, jig grinding product overlap, and Japanese-domestic market focus.
• Kobelco (Kobe Steel) Industrial Compressor Division: Kobe Steel's industrial machinery division produces screw compressors and oil-free compressors for the Japanese market. Direct domestic competitor to Mitsui Seiki's Z-screw compressor portfolio, serving similar Japanese factory and industrial compressed-air customers.

Broad incumbents

• Atlas Copco: Global market leader in industrial compressors and a major machine tool/vacuum solutions provider. Broad incumbent competitor to Mitsui Seiki's compressor business (especially GA/GR oil-injected screw and oil-free ranges) with deeper digital platform (SmartLink) and global service network.
• Ingersoll Rand: Global diversified industrial manufacturer of compression equipment, fluid handling, and process solutions. Overlaps with Mitsui Seiki on industrial oil-free and oil-lubricated screw compressors, with much broader global scale and IoT-enabled service offerings.

Market position

Strengths5 records

Weaknesses5 records

Competitive moat5 records

Key risks5 records

Key highlights6 records

Customer concentration

• YouTubeyoutube.com/channel/UCdf_cAbdKErAEr7y-1zxw0g/featured
• Facebookfacebook.com/mitsuiseikikogyo

Revenue estimate

Valuation estimate

Number of profiles

Profiles3 records

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 Mitsui Seiki