The company set up its operation as a packing maker for wrist watch in 1967,
since then we emphasize our power for developing precision rubber parts.
By rapid progress of electric equipments, the machines have developed to multiple and high performance, and its structure is complicated and compact.
Rubber products are required to cooperate with other machine parts, absorb shock, open-close performance and more of various demands.
We listen to our customers' needs and we enable to downsize and complicated moulding by continuous material study, research and development.
KEF, as an advanced rubber products manufacturer, we seek for capability of rubber and develop our technical area to fulfill our customers' needs.

1. The company cares for its employees and the employees do their best in order to contribute to the company.
2. The company cares for its customers to grow and develop with them in the world.
3. The company cares for its products and supplies the highest technology and quality products on time.


THE COMPANY LOGO MARK The earth represents environmental preservation and our world-wide progress. The blue color around the earth symbolizes our employees, the green color stands for our customers and the red color is drawn as our products.


Name: KEF Corporation
Address: 1607 Mutsuzaki, Sakura Chiba Zip Code: 285-0812
Established: 1-Aug-67
Capital: JPY 98,000,000
President: Yoshitake IYOKU
Number of employee: 35 (350 employees in the whole group of KEF)
Contents of business: Manufacture and sales of rubber products (such as gaskets/packing)
Sales volume: JPY 2,100 million (March 2018 KEF Group results)
Main Bank: Chiba Bank, Ltd. Sakura branch/ MUFG Bank, Chiba Branch/The Shokochukin Bank, Chiba Branch/ Mizuho Bank, Ltd. Chiba Branch
Affiliated Companies: KEF (Hong Kong) Co., Ltd. 
KEF Corporation of America
KEF (Shenzhen) Company Limited
KEF Corporation, Chiba, succursale de Geneva
KEF Corporation(Switzerland Branch)
KEF (Thailand) Company Limited, Samutprakarn, Thailand


Aug-67 Kyowa Kako was established as a limited-liability company dealing with wrist watch packing supplier in Shibayama, Funabashi Chiba.
Jan-70 A sales agent for the Western Europe was founded in Switzerland. Then the overseas market expanded to areas in Southeast Asia and the U.S.
Nov-77 Moved the whole operation from Funabashi to Sakura in Chiba.
Jun-78 Changed the corporate body from the limited-liability company to a joint-stock company.
Dec-85 Got a license to display the certificate of Japanese Industrial Standards. O-ring JIS B2401
Jun-90 Completed construction of the new office building for the company.
Jul-91 Started to develop materials for hard disk drives for computers and began sales for packing used in hard disk drives.
Aug-95 Established Kyowa Kako (Hong Kong) Co., Ltd.
Aug-97 Certified ISO9002 (in head quarter and factory).
Jan-98 Started Kyowa Precision Rubber and Plastics Factory in China.
Mar-00 Increased its capital from JPY 80,000,000 to JPY 98,000,000.
Aug-00 Certified ISO9001 (in head quarter and factory).
Dec-00 Founded "KEF Corporation of America".
Jan-01 Changed its company name from Kyowa Kako Co., Ltd. to KEF Corporation. Also, Hong Kong office changed her name to KEF (Hong) Co., Ltd. accordingly.
Apr-01 Certified ISO9002 in KEF (Hong Kong) Co., Ltd. And the factory in China.
Jun-01 Awarded "Equal Employment Promotion Company Award for Effort (the Minister of Health, Labor and Welfare)". Web site:
Sep-01 Increased production facilities in Kyowa Precision Rubber and Plastics Factory in China.
Apr-02 Started the sales of packing for digital cameras.
Dec-02 Started to develop materials for inkjet printers and began with the sales of packing for those application.
May-03 Started its operation in the second factory in Kyowa Precision Rubber and Plastics Factory.
Jun-03 Certified ISO9001 in KEF (Hong Kong) Co., Ltd. And the factory in China.
Jul-03 Established KEF Corporation, Chiba succursale de Geneve, Switzerland
Mar-04 Awarded by The Nikkan Kogyo Shimbun Ltd. "Prize for Encouragement" by dust-proof gaskets.
Aug-04 Built more facilities in the factory in China.
Jan-05 Certified ISO14001 in head quarter and factory.
Mar-05 Certified ISO14001 in KEF (Hong Kong) Co., Ltd. And the factory in China.
Sep-07 Established KEF Research and Development Centre in Venture Plaza, Funabashi.
Jul-08 Elected one of "Introducing 300 of Japan's Dynamic Monozukuri (manufacturing SMEs" by the Ministry of Economy, Trade and Industry.
Feb-10 Collaborated to improve extremely high pressure-proof packing for space use, and assembled in a wrist watch of astronaut. Received testimonial letter from Seiko Epson for the success.
Mar-11 Switzerland branch moved from Geneva to Neuchâtel
Mar-13 Yamagatananyo Plant established
Jul-15 KEF (Thailand) Company Limited established
Oct-16 China plant monopolization,Change company name from Kyowa Precision Rubber and Plastics Factory to KEF(Shenzhen)Company Limited.
Aug-17 Certification ISO 13485 (Medical Equipment)
Mar-18 KEF Micro O-ring Registered as “JIS B 2240-1” in 2018 according to the Ministry of Economy, Trade and Industry of Japan’s "New market creation standardization system"

Hong Kong Office

Hong Kong Office
Name: KEF(Hong Kong) Company Limited
Established: Aug-95
Capital: HK$5,000,000
Address: Unit 910, 9/F., Tower B, New Mandarin Plaza, No 14 Science Museum Road, Tsim Sha Tsui East, Kowloon, Hong Kong
PHONE: +852-2384-1954



China Factory

China 1st Factory
China 1st Factory

China 2nd Factory
China 2nd Factory
Name: KEF (Shenzhen) Company Limited
Established: Jan-98
Address: Baozi Industrial, Kengzi Town Longgang District, Shenzhen, Guangdong Province, China
PHONE: +86-755-8413-5760
FAX: +86-755-8413-5716


Switzerland Branch

Name: KEF Corporation, Chiba, Succursale de Neuchâtel (Switzerland Branch) Sales in Europe
PHONE: +41-22-734-4120
FAX: +41-22-734-4122


KEF (Thailand) Company Limited
Name: KEF (Thailand) Company Limited
Established: July 2015
Address: 55/61 Moo 15 Bangsaotong Sub-District, Bangsaotong District, Samutprakarn Province 10540 Thailand
PHONE: +66-2-136-7361
FAX: +66-2-136-7362