| 1948 |
Founded by Mr. Masao Muto at Nishi-shinbashi, Tokyo. Started selling automotive parts. |
| 1948-03 |
1948年3月（昭和23年3月） |
| 1953 |
Musashi Oil Seal Mfg.Co.,Ltd. Was established with a capital of 1.5 million. |
| 1953-01 |
法人組織に改め、資本金１５０万にて武蔵オイルシール工業を設立 |
| 1958 |
Funabashi Factory was constructed in Chiba Pref. |
| 1958-12 |
千葉県船橋市に船橋工場を開設 |
| 1964 |
Became a factory approved to allow JIS (Japanese Industrial Standard) Labeling of oil seal produced under JIS_B2402. |
| 1964 |
Osaka sales office was established in Osaka city, Osaka Pref. |
| 1964-06 |
オイルシール（ＪＩＳＢ２４０２）の日本工業規格表示認定工場となる |
| 1964-09 |
大阪市に大阪営業所を開設 |
| 1966 |
Became a factory approved to allow JIS (Japanese Industrial Standard) Labeling of O-ring produced under JIS_B2401. |
| 1966-10 |
Ｏリング（ＪＩＳＢ２４０１）の日本工業規格表示認定工場となる |
| 1967 |
Sapporo sales office was opened in Sapporo city, Hokkaido. |
| 1967 |
Head Office was moved to Roppongi, Minato-ku,Tokyo. |
| 1967-08 |
札幌市に札幌営業所を開設 |
| 1967-12 |
本社を東京都港区六本木に移転 |
| 1969 |
Fukuoka sales office was opened in Fukuoka city,Fukuoka Pref. |
| 1969-04 |
福岡市に福岡営業所を開設 |
| 1976 |
Otawara factory was constructed in Otawara City, Tochigi Pref. |
| 1976-10 |
栃木県大田原市に大田原工場を開設 |
| 1979 |
Otawara No.2 Factory was constructed. |
| 1983 |
Sendai sales office was opened in Sendai city, Miyagi Pref. |
| 1985 |
Distribution center was established at the Otawara factory. |
| 1988 |
Otawara No.4 factory was constructed. |
| 1989 |
Otawara No.5 factory was constructed. |
| 1996 |
Funabashi No. 2 factory was constructed to expand the development, testing and experiment departments. |
| 1998 |
Funabashi Factory obtained an international standard,ISO 9001 certification. |
| 2003 |
The capital was increased to 48 million yen. |
| 2004 |
No.2 distribution center was constructed. |
| 2005 |
Nagoya sales office was opened in Nagoya city, Aichi Pref. |
| 2008 |
Obtained ISO 9001 certification for all business divisions including the head office and sales division. |
| 2012 |
The capital was increased to 62 million yen. |
| 2012 |
Otawara No.6 factory was constructed. |
| 2021 |
Tokyo Sales Office moved to Misato City, Saitama Pref. |
| 2024 |
Otawara No.7 factory was constructed. |
| 2024 |
Distribution center relocated to Otawara No.7 factory. |
| 2024 |
New automated warehouse installed at Otawara No.7 factory. |
