ƒ Tominaga & Co.,Ltd.
    We focus on the import and sales of water jets and diesel engines for vessels. We promptly deliver necessary
    parts and provide superior service through our direct workshops and local partners, resulting in an
    excellent sales and delivery record for numerous engines.
    We offer sales and post-sales support of various plant facilities and equipment
    (rotary pumps, double diaphragm pumps, flow meters, powder conveyers, dispersing emulsifier machines, etc.).
    We are a one-stop shop for building new manufacturing facilities from design, production and installation to pilot
    runs and deliveries in the engineering field (greases, paints, adhesives, chemicals).
    We develop various engines for pump and generator used on land as well as
    generators and associated accessories, gas turbines and associated parts, KOHLER diesel electric generators,
    HATZ small air-cooled diesel engines, air filters for gas turbines or industries use, gas engine ignition systems,
    gas admission valves, air starters, air conditioners for vessels, generators for vessels, marine products such as water-cooled
    exhaust silencers, power supply vehicles specialized for TV relay, and specialized air conditioners.
  • Tominaga & Co.,Ltd.
    ‘We offer the world’s leading products to customers through our accumulated technologies,
    and try to improve our service and to enhance our business performance continuously for the future.’

Foundation and History

Since starting out in business as a retailer named ‘Tominaga Shoten’ in 1899, we sold chiefly iron steel and nonferrous metal to domestic and overseas customers as an agency of the current Nippon Steel & Sumikin Coated Sheet Corporation for about 50 years, until we changed our name to ‘TOMINAGA & CO., LTD.’ in July 1948 and entered into a dealership from the Detroit Diesel Allison Division of General Motors, US as its general sales agency in Japan.
After entering into the dealership, we have been importing and selling products, and maintaining our infrastructures such as Service Facilities and parts center chiefly on the basis of the Engine Division. And we are highly appreciated by many domestic customers in various fields.
Currently, we are playing an active role as sales and service agency in Japan of MTU Germany (series 4000 and under), which was merged with the Detroit Diesel Corporation in April 1998, and we are making efforts to satisfy customers in wider fields, including not only marine vessels but also rail vehicles and industrial machines.
In the future, we will also put our efforts into sales and service of gas engines as well as diesel engines in order to address environmental issues.

Motto and Business policy

‘We offer the world’s leading products to customers through our accumulated technologies, and try to improve our service and to enhance our business performance continuously for the future.’
For more than half a century, importing and selling diesel engines, dealing in various high quality industrial equipment and units, receiving orders collectively for various equipment and manufacturing facilities, we have developed service networks throughout Japan as well as selling the world’s leading products in order to improve our after-sales service.
We received ISO9001 certification in May, 2004 as we are aiming to be a company that can satisfy customers’ requirements further, pursuing ‘company quality’ as well as ‘product quality’.

Business activities

Engine division,Plant Machinery division,Power plant division, read more.....


Company Name
June 29, 1939
120 million yen (Authorized capital: 480 million yen)
Main Stockholders
Sumitomo Mitsui Banking Corporation, Resona Bank, Ltd.
MUFG Bank, Ltd.
Tokio Marine & Nichido Fire Insurance Co., Ltd.
Service Facilities
3-6-2, Nihonbashi Honcho, Chuo-ku, Tokyo 103-0023
Funabashi Service Facilities
2-6-3, Nishiura, Funabashi, Chiba Pref. 273-0017
Kyusyu Service Facilities
2848, Aoyagi, Koga, Fukuoka Pref. 811-3134
Nagasaki Branch Office
1-1245-4, Tominohara, Oomura, Nagasaki Pref. 856-0805
Plant Service Center
5-9-1, Azuma-chou, Koshigaya, Saitama Pref. 343-0826
Osaka Branch
2-6-8, Nishitenma, Kita-ku, Osaka 530-0047
Kansai Service Facilities
3-60,Minamiyama,Issai-cho,Tatsuno,Hyogo Pref.679-4016
Nagoya Sales Office
4-806, Ohmori, Moriyama-ku, Nagoya, Aichi Pref. 463-0021
GT Service Center(Gas Turbine Dept.)
153, Hojomiyanomachi, Himeji, Hyogo, 670-0948
Parts Center
750-3, Shindachimakino, Sennan, Osaka 590-0522
Board members
Senior Managing Director, General Manager of Osaka Office and Headquarter of Sales    TSUTAE TAKEUCHI
Director, Senior Manager of After Sales Dept. (Engine Division)    MORIAKI UEKI
Director, General Manager of General Affairs and Finance    KUNIHIKO TAHARA
Director, General Manager of Power Plant Division    JUNICHIRO TAGAWA
Director, Senior Manager of Engine Sales Dept. (Engine Division)    KENGO KAWAI
Auditor    IZUMI KOCHI
Approximately 150
Business hours
9:00  ~  17:15
Administration & Accounting Dept., Engine Div., Plant Machinery Div., Power Plant Div. Service Facilities: Funabashi, Kansai, Kyushu
Sales Office: Nagoya, Nagasaki
Annual Sales
Approximately 10 billion yen
Main Financing Bank
Sumitomo Mitsui Banking Corporation
Resona Bank, Ltd.
MUFG Bank, Ltd.


- Scroll to the right -

  • Jan.1899
    Tominaga started
  • Jun.1939
    Under the wartime controlled economy, we reorganized business as Tominaga Shoten Co., Ltd. , and then became an exclusive agency of Tominaga Steel Corporation (a predecessor of current Nippon Steel & Sumikin Coated Sheet Corporation).
  • Jul.1948
    As a result of the dissolution of the former Mitsui & Co., Ltd., we absorbed volunteers from the company, especially members in charge of hardware, and changed our company name to Tominaga & Co., Ltd. to restart our business. And along with resumption of trading, we expanded into import and export fields as well as the initial domestic sales chiefly of iron, steel and nonferrous metal. Our capital at the time was 3 million yen.
  • Jun.1950
    Our capital was increased to 10 million yen.
  • Oct.1950
    We have shifted the center of gravity of our sales sequentially to the machinery division since we entered into a dealership from the Diesel Engine Division of General Motors US to sell diesel engines throughout Japan.
  • Sep.1951
    Our capital was increased to 30 million yen.
  • Jan.1970
    Our headquarters were transferred from Osaka city to Nihonbashi, Chuo-ku, Tokyo.
  • Jul.1970
    DDC (GM) Diesel Engine Service Plant (current Funabashi Service Facilities) was constructed in Funabashi-shi, Chiba.
  • Sep.1970
    We entered into an agency agreement with Allison Transmission Div. of General Motors corp.
  • Feb.1971
    Nagoya Sales Office (under the direct control of the Plant Machinery Division) was established in Nishi-ku, Nagoya.
  • Oct.1972
    Our capital was increased to 60 million yen.
  • Jan.1974
    DDC (GM) Diesel Engine Service Plant (current Kansai Service Facilities) was constructed in Himeji-shi, Hyogo.
  • Apr.1976
    Our capital was increased to 120 million yen.
  • Oct.1977
    We entered into an agency agreement with the Allison Gas Turbine Div. of General Motors corp (current Energy & Marine Operations of Rolls-Royce corp).
  • Oct.1978
    DDC (GM) Diesel Engine Service Plant (current Kyushu) was constructed in Fukuoka-shi, Fukuoka.
  • Jul.1979
    Parts Center was established in Osaka-shi, Osaka, and was later transferred to Ikeda-shi.
  • Oct.1981
    Approved as a contractor for steel structures, we expanded into design and construction of plants.
  • Feb.1982
    We received the right to manufacture Stratco Grease Contactors (grease reactor kettles) in Japan, technically collaborated with STRATCO Inc., US.
  • Jan.1986
    We started sales and service of AT, MT and HT automatic transmissions of General Motors.
  • Dec.1990
    Kobe Office was established in Chuo-ku, Kobe-shi, Hyogo, and was transferred to Akashi-shi later.
  • Apr.1991
    Kyushu Service Facilities was transferred to and newly constructed in Koga-shi, Fukuoka.
  • Nov.1995
    Parts Center was transferred to Sennan-shi, Osaka.
  • May.1996
    Service Center (under the direct control of the Plant Machinery Division)was established in Matsudo-shi, Chiba
  • Feb.1998
    We entered into a sales and service agency agreement for diesel generators with US Kohler Co.,Ltd.
  • Apr.1998
    We entered into a sales and service agency agreement for diesel engines made by MTU, a member of the Daimler Chrysler Group.
  • Oct.2000
    We received general dealership in Japan to sell and service 099, 183, 396, 2000 and 4000 series made by MTU, a member of the Daimler Chrysler Group.
  • Apr.2004
    Funabashi Service Facilities was transferred to and newly constructed in Nishiura, Funabashi-shi, Chiba.
  • May.2004
    We were certified according to ISO9001.
  • Nov.2004
    Akashi Office was transferred to Himeji-shi,Hyogo.
  • Mar.2009
    We entered into agency agreement (Water Jet) with C.W.F.HAMILTON & CO LIMITED,CHRISTCHURCH,NEW ZEALAND.
  • Dec.2011
    Tokyo headquarters was transferred.New location:3-6-2, Nihonbashi Honcho, Chuo-ku, Tokyo 103-0023
  • Apr.2024
    Himeji Service Facilities was transferred to Tatsuno-shi Hyogo.(Kansai Service facilities)


1 Company Policy

We offer the world’s leading products to customers through our accumulated technologies, and make efforts to improve our service and to enhance our business performance continuously for the future.

Noritsugu Konishi
November 29, 2007

2 Organization


3 Conceptual Chart of Quality Management

Conceptual Chart of Quality Management Image

4 Customers Satisfaction

4-1. Steps to Cope with Customer Complaints

We cope with customer complaints according to the following procedures to prevent reoccurrence.


4-2. Survey of Customer Satisfaction

To improve on product quality, we are performing survey on customer satisfaction annually.

5 Scope of the Quality Management System

5-1. Division: Whole Company

5-2. Product and Service

a. Sales, inspection and maintenance of imported machinery including engines
b. Design, installation of chemical plant including lubricating grease production facility and construction management of the structure

5-3. Applicable Standards

ISO 9001:2015


Engine Division

This division has sold diesel engines more than 50 years. We maintain direct workshops capable of supporting your demands, and we have established a network with our partner companies across Japan. We offer various support including prompt delivery of needed parts, and we have acquired the skills and knowledge that ensure the trust of our various customers, including government offices. As a result, we have sold and delivered a large number of engines.
We recently started to sell CAT as a small vessel engine, which makes our product lineups broader and we cover various power models.
Since 2009, we have also been selling Hamilton's propulsion "waterjet" in order to broadly meet the needs of our customers.

Plant Machinery Division

We have established our knowledge and skills through numerous deliveries of various facilities and equipment and have been importing from overseas since 1965. We have played the role of sole import agent in Japan and provided post-sales supports in the facilities and equipment field for many years, including various positive displacement rotary pumps, double diaphragm pumps, flow meters, powder conveyers, dispersing emulsifier machines, versators, and tube-cleaning machines.
In the plant engineering field, we serve as a one-stop shop by providing design, production, installation, construction, pilot runs and delivery of new factories furnished with manufacturing facilities for paints, resins, adhesives, and greases, all of which contribute to our customers’ improvement in streamlining, labor/energy saving, automation, and product quality.
In particular, we are one of the three biggest engineering companies which dominate the world market in grease-plant engineering.

Power Plant Division

With more than 30 years of history, our division has been selling and supporting a number of products by importing them from the world’s best manufactures. The products include diesel engines, gas engines and gas turbines for various applications, as well as relevant accessories and parts, such as air filters and air starters for gas turbines, ignition systems, and gas admission valves. We have continuously been trying to solve emerging problems in order to support the market; for example, we are working on the development of a high stability generator for vehicle use in the TV broadcasting industry and air conditioners for vehicles and vessels. We recently reorganized the land engine department to provide high quality, total engineering services, such as the integration of generators with associated accessories, the packaging of engine pumps and various engines, ranging from 5 kW to 3,000 kW, including small air-cooling diesel engines, primarily for land use.


Ozu Bldg., 3-6-2, Nihonbashi-Honcho,
Chuo-ku,Tokyo,Japan 103-0023
TEL: 81-3(3639)5311 (Main switchboard)
Osaka Branch
Do Bldg.,2-6-8, Nishi-tenma, Kita-ku,
Osaka-city,Osaka 530-0047
TEL: 81-6(6361)3836 (Main switchboard)
2-6-3,Nishiura, Funabashi-city, Chiba 273-0017
TEL: 81-47(433)6181 (Switchboard)
3-60,Minamiyama,Issai-cho,Tatsuno,Hyogo 679-4016
TEL: 81-791(66)3600 (Switchboard)
2848,Aoyagi,Koga-city,Fukuoka 811-3134
TEL: 81-92(944)3211 (Switchboard)
Omori Bldg.,4-806,Omori, Moriyama-ku,
Nagoya-city,Aichi 463-0021
TEL: 81-52(798)5911 (Switchboard)
Nagasaki 856-0805
TEL: 81-92(944)3211 (Switchboard)
GT Service Center
(Gas Turbine Dept.)
TEL: 81-79(282)7888 (Switchboard)
Parts Center
750-3, Shindachi-makino,Sennan-city,
Osaka 590-0522
TEL: 81-72(485)4884 (Switchboard)
Plant Service Center
5-9-1,Azuma-chou,Koshigaya,Saitama 343-0826
TEL: 81-48(961)1600 (Switchboard)