1950
- Apr.
- Founded by Minoru Matsushita as YAMATO KOKI in Nagoya-shi, Aichi-ken
1954
- Sep.
- Reorganized YAMATO KOKI as a corporation. Established SANWA SEIKI CO., LTD. with a capital of 1 million yen.
1956
- Sep.
- Established Tokyo Branch Office in Chiyoda-ku, Tokyo (Tokyo Sales Office moved to current address in 2001)
1965
- Apr.
- Established Hamamatsu Branch Office in Hamamatsu-shi, Shizuoka-ken (Hamamatsu Branch moved to current address in 2008)
1981
- Aug.
- Established Ota Sales Office in Ota-shi, Gunma-ken (merged with Saitama Sales Office in 2006)
1982
- Apr.
- Established Shiga Manufacturing in Moriyama-shi, Shiga-ken
1983
- Jul.
- Established Kawagoe Sales Office in Kawagoe-shi, Saitama-ken (Saitama Sales Office moved to current address in 2006)
1985
- Sep.
- Established Fujisawa Sales Office in Fujisawa-shi, Kanagawa-ken (Kanagawa Sales Office moved to current address in 2024)
1998
- Aug.
- Moved the head office to the current address due to the construction of new building
1999
- May.
- Increased the capital to 62.28 million yen
2001
- Apr.
- Joined OSG Consolidated Group
2006
- Nov.
- Established Fukushima Sales Office in Fukushima-shi, Fukushima-ken (Moved to current address in 2019)
2007
- Oct.
- Established SANWA SEIKI (THAILAND) CO., LTD. in Bangkok, Thailand
2009
- Feb.
- Established Akashi Sales Office in Akashi-shi, Hyogo-ken (Moved to current address in 2014)
2011
- Oct.
- Established SANWA SEIKI CO., LTD. (PINGHU) in Pinghu, Zhejiang, P.R.China
- Nov.
- Established PT.SANWA SEIKI INDONESIA in Jakarta, Indonesia by merging with PT.OSG Indonesia
2013
- Aug.
- Established SANWA SEIKI (THAILAND) CO., LTD. MD TOWER BRANCH in Bangkok, Thailand
2015
- Feb.
- Established PT.SANWA SEIKI INDONESIA KARAWANG BRANCH in Karawang, Indonesia
- Jun.
- Established Hiroshima Sales Office in Hiroshima-shi, Hiroshima-ken
- Nov.
- Established Shiga Sales Office in Moriyama-shi, Shiga-ken
- Dec.
- Established Higashi Mikawa Office in Toyokawa-shi, Aichi-ken
2016
- Feb.
- Established Saga Sales Office in Saga-shi, Saga-ken (Moved to current address in 2020)
- Nov.
- Merged with KASUGA SEIMITSU KOGYO CO., LTD. and established Gunma Sales Office in Ota-shi, Gunma-ken
2019
- Oct.
- Established Kurashiki Sales Office in Kurashiki-shi, Okayama-ken