| 1948 | Tomiji Okubo, the first generation, founded the company. |
| 1950 | Started manufacturing bicycle accessories and handlebar covers for motorcycles. |
| 1971 | Moved the factory to the present location. |
| 1985 | Registered the Yamamaruto trademark. |
| 2003 | Tomio Okubo, the 2nd generation, established Okubo seisakusho Inc. |
| 2006 | Tomihiko Okubo, the third generation, became the representative director. |
| 2017 | Opened “Socca” Cycle Goods Mart Laboratory on Rakuten Market. |
| 2018 | Completed our new building as a training headquarters and office. |
