| Company name | OHYO KOKEN KOGYO Co., Ltd. | |
| Establishment | 16-September-1963 | |
| Capital | JPY30,000,000 | |
| Number of employees | 66(as of November 2017) | |
| Offices | ||
| *Head office (Factory) | 1642- 26 Kumagawa Fussa-city Tokyo 197-0003 Japan | |
| *Higashimatuyama Factory | 88-77 Shingo Higashimatsuyama-city Saitama 355-0071 Japan | |
| *Osaka sales office | 4-4-63 Miyahara Yodogawa-ku Osaka-city 532-0003 Japan | |
| *Kyushu works | 293 Hondosumachi Tosu-city Saga 841-0026 Japan | |
| Website | https://www.oken.co.jp | |
| * September 1963 |
Established OHYO KOKEN KOGYO Co., Ltd. It was established at Shinjuku-ku Tokyo, succeeding the production of optical materials and radiation detecting materials, which were developed by optical laboratory of Tokyo University of Education. |
| 1968 |
Established manufacturing know-how of large-scale radiation detecting materials |
| 1976 |
Merged radiation instruments division of Tokyo Genshi Kogyo Co.,Ltd. Started to supply radiation measuring instruments |
| 1979 |
Moved crystal manufacturing division to Higashimatuyama city in Saitama-pref. |
| 1982 |
Moved head office and radiation instruments division to Fussa city in Tokyo |
| 1984 |
Enlarged Higashimatuyama Factory |
| 1985 |
Opened Osaka sales office near Shin-Osaka Station |
| 1990 |
Opened Kyushu Works at Tosu-city in Saga-pref. |
| 1992 |
Rebuilt Head office |
| 1996 |
Built second crystal factory at Kodama in Saitama-pref. |
| 2002 |
Expanded crystal manufacturing line at Higashimatuyama factory |
| 2006 |
Constructed new Kyusyu works |
| 2012 |
50th anniversary of company foundation Annual sales JPY1,540,000,000 |