| 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 |