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Welcome to our English Website! We hope that our site will be informative and valuable to you when you wish to learn more about KOKEN LTD. and our products.

Today KOKEN LTD. is proud to be the leading manufacturer of respiratory protective devices in Japan. Never satisfied with this success, however, we are advancing into the fields of environment-preservation and medical-care industry, utilizing our unique technologies developed through a long period of R & D effort.

Although we have been focusing mainly on the Japanese market so far, we have a strong desire to increase our presence in the growing global market from now on. Our Website will provide you with the opportunity to look inside our organization and know our uniquely-developed technologies.

We hope that this English Website will also serve as a catalyst for inviting joint research and development projects and joint-ventures or business tie-ups, and we are more than happy to see that those who contact us through our Website will become our new shareholders.

We promise to improve our Website according to your needs and hope to serve you soon.

Best regards,

Shinichiro Sakai
Chairman and Chief Executive Officer of KOKEN LTD.

Human life is the highest value. Committed to CLEANLINESS, HEALTH and SAFETY, which are directly related to human life, we, at KOKEN, engage ourselves in creating products with originality and sophistication, thus contributing to the society.

To realize this purpose, all employees are required to demonstrate maximum imagination and creativity, which are the source of human dignity. As a consequence, our fundamental managerial policies, “don’t play second fiddle to other competitors” and "conduct research thoroughly" are materialized, and will result in continuous techological innovation and creative product development.

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May, 1943

  Incorporated: December, 1963
  Capital: JPY 674 million
  Fiscal Term: End of December
  Security Code: 7963/Japan Association of Securities Dealers Automated Quotations
market of Tokyo Stock Exchange )
  Representative: Shinichiro Sakai : Chairman & CEO
  Number of Employees: 268  *As of December, 2016.
  Descriptions of Business:
Production and sales of occupational personal protective equipment (e.g. particulate respirators, chemical cartridge respirators, SCBA, etc.)
Designing and installation of environmental quality improvement equipment (e.g. push-pull ventilation system).
Production and sales of OXILYZER, acid-electrolyzed water generator.
Production and sales of KAGAMI-NAISHI, automatic endoscope washer.
Production and sales of KOACH, open clean system.
Sales of EcoBeam, magnetic remover of rust and scales.
Production and sales of AQUA FLASH, soil and groundwater purifying system.
Research and incubation of microorganism.
Business Establishment:
    Head Office: Tokyo
    Laboratory: Hannou
Super Clean Technical Center:
    Techno-Yards: Sayama, Gunma, Tokorozawa , Nakai & Ranzan
    (Techno-Yards: KOKEN’s strategical base camps for R&D/manufacturing; coined term implying a creation of originality and value)
    Logistics Center: Saitama
    Local Offices: 16 cities across Japan
    Showroom: Tokyo , Nagoya , Osaka & Kyushyu
  Affiliated Company:
    SIAM KOKEN LTD.(Thailand)

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Koken will consider the value of human life the most sublime matter, commit itself to business related to Cleanliness, Health and Safety that directly governs human life, and provide our society with products based on technology of high originality.

In designing products, Koken will keep customer’s view point, endow the design with performance and safety enough to protect life, and which design meets or surpasses pertinent quality standards.
In producing or manufacturing products, Koken will apply statistic method, keep a condition where production or manufacturing process is fully controlled within a range of scattering or dispersion that can prove it to be sufficient to be reliable.
In designing through production or manufacturing, Koken will always improve its work and produce a condition where a strong competition can be maintained.
Regarding performance and use of products, Koken will keep users always informed correctly of them and make users avoid their misuse.
In process of work, Koken will give first priority to its worker’s safety and health.

Koken Ltd.
Tsutom Murakawa
President & COO

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 Koshinkai Kenkyujo was established by Yoshijiro Sakai, the Founder.
Started the research of occupational safety and health protective equipment.
Koshinkai Kenkyujo was incorporated. A particulate respirator under research passed the national standard.
Koken Ltd. was established and served as an organization in charge of production and sales. Koshinkai Kenkyujo was assigned to conduct research and successfully developed “micron filter,” an electro-static filtering material which presently makes up the mainstream of particulate respirators.
Hannou Laboratory, where basic research has been performed, was established.
Koken was awarded the Award of the Minister of International Trade and Industry for the contribution to the safety of mining.
Koken received a letter of appreciation from the managing director of the technical research department of the then-Defense Agency for cooperation in performing experimental R&D of air-purifying equipment.
Yoshijiro Sakai was awarded the Medal with Purple Ribbon and the Achievement Award of the Minister of Labor, for contribution to occupational safety.
The development of “Alpha-ring filter”, the Japan’s first integrally-molded paper filter with high performance, was completed.
Koken Bosai (accident prevention) System was established and served as an organization in charge of sales. Koken Ltd. was assigned to conduct production and R&D.
Koken received a letter of appreciation from the managing director of the technical research department of the then-Defense Agency for cooperation in performing experimental R&D of new protective respirator and new protective clothing.
Koken completed the merger with Koshinkai Kenkyujo and Ninomiya Production Center and increased its capital to JPY380 million. Koken received a major order of respirators from the then-Defense Agency and successfully established a full-scale production system.
Koken registered its name on the Tokyo Over-the-Counter Stock Exchange Market and increased its capital to JPY644.6 million.
Koken completed the merger with Koken Bosai System. All factories and production centers were re-named to “Techno-Yard.”
The construction of the Sayama Techno-Yard was completed.
Cancer control substance was developed at the Tokorozawa Laboratory and disclosed. New R&D facility at the Tokorozawa Laboratory was constructed.
Koken added Oxilyzer, a strong acid electrolyzed water generator, and push-pull ventilation system on product line, as part of environmental quality improvement equipment-related business. Koken respirators contributed in the recovery operations of the Great Hanshin Earthquake and the Tokyo Subway Sarin Gas Attack. Newly-developed personnel system, or Total Personnel System, was installed.
Oxilyzer was approved as medical equipment by the Ministry of Health and Welfare. The construction of the Nakai Techno-Yard and Nakai Logistics Center was completed.
Entire organization was approved under ISO9001. The construction of the Gunma Techno-Yard was completed. EcoBeam, a non-chemical water treatment system, was added on product line as a part of environmental quality improvement equipment-related business.
Koken’s SCBAs contributed in the recovery operation of the criticality accident at the nuclear power plant in Tokai Village, emergency response operation of the volcano eruption in the Miyake Island, and as emergency measures against dioxins generated in the trash incinerating facilities. Koken Laminar, a unit-type open-style pull-pull ventilation system, was introduced.
Particulate respirators using the newly-developed “Mighty Micron Filter,” corresponding to the new Japanese national assay standard, were introduced. Products for nuclear, biological and chemical (NBC) events (emergency evacuation respirators for NBC attacks and strong acid electrolyzed water disinfection shower system) were developed and introduced.
The Gunma Techno-Yard was approved under ISO 14001 Environment Management System (Assessment registration). Two new products (breath-response PAPR “Breath-Link Model 10” and polluted soil purification system Aqua Flush, using UV-rays and electrolyzed water) with the use of world’s first innovative technology were simultaneously introduced.
The Nakai Techno-Yard and Nakai Logistics Center were approved under ISO Environment Management System (Assessment registration).
Open-draft “Laminar Table HD-01” and breath-response PAPR “Model BL-50” were introduced. Koken canceled the Over-the-Counter registration at the Japan Securities Dealers Association (JSDA) and went public on the Japan Association of Securities Dealers Automated Quotations (JASDAQ) market.
The Tokorozawa Techno-Yard was approved under ISO 14001 Environment Management System (Assessment registration).
“Kagami-Naishi,” a fully-automated endoscope washer, was approved as medical equipment under the pharmaceutical affairs law. “Lifemaster,” emergency respirator for evacuation from fire and special evacuation, was introduced. Koken launched a recycling system of used filters for particulate respirators.
Recycling system of used chemical cartridges was started.


Development of innovative technologies, "Nano-fiber filtar" and "Open clean bench," was disclosed.
Logistics center (now called Saitama Logistics Center) was re-located from Kanagawa Pref. to Saitama Pref.


Company`s shares listed on JASDAQ-OSE integrated market after merger of JASDAQ Securities Exchange into Osaka Securities Exchange.
KOACH showroom opened.
  KOKEN Super Clean Technical Center opened.


Overseas subsidiary SIAM KOKEN LTD. established in Chonburi Province,Thailand.
Ranzan Techno-Yard established in Ranzan, Saitama Prefecture.
Company's shares listd on the JASDAQ Standard market follwing merger of the Osaka Securities Exchange with the Stock Exchange.

Business operations commence at SIAM KOKEN LTD.


Shinichiro Sakai, chairman & CEO. was awarded the Order of the Rising Sun, Gold Rays with Rosette in a 2016 Spring conferment ceremony.

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