1933 July Established as the Ohkura Electric Research Institute, an affiliate of the Henmi Bamboo Slide Rule Campany.
1936 December Incorporated as the Ohkura Electric Research Institute, Ltd. with capital of JPY300,000.
1943 December Changed company name to Ohkura Electric Co.,Ltd.
1947 February Built Tokyo Factory in Suginami-ku, Tokyo
1962 October Listed on the Second Section of the Tokyo Stock Exchange with capital of JPY260 million. 
1964 February Built Sakado Factory in Sakado, Saitama
1984 May Opened the Wako Technology Center in Wako Saitama.
1984 October Increased capital to JPY2,327.2 million.
1986 September Listed on the First Section of the Tokyo Stock Exchange.
1986 December Built Misato Factory in Misato-Machi, Kodama-gun, Saitama
1988 October Increased capital to JPY4,061.2 million.
1990 October Built Hokkaido Plant in Eniwa, Hokkaido.
1997 February Accredited under ISO 9001
2001 May Moved the head office to Wako, Saitama
2001 October Reorganization process was begun under the Japanese civil rehabilitation law
2002 January Sold the Telecommunication Systems Department
2002 June Decreased capital to JPY10 million
2002 July Moved the head office to Misato, Saitama
2002 August Completed the reorganization process under the Japanese civil rehabilitation law.
2003 January Accredited under ISO 9001 /2000(Misato Head Office/Factory)
2004 April Built head office/factory in Sakado, Saitama
2005 January Accredited under ISO14001/1996(Sakado Head Office/Factory)
2005 August Built second factory in Sakado,Saitama 
2006 Febrary Accredited under ISO14001/2004(Sakado Head Office/Factory).
2010 November Accredited under ISO9001/2008(Sakado Head Office/Factory/Branch Office) 
2013 November Ohkura Electric Co., Ltd became a consolidated Subsidiary of Y.A.C. Co., Ltd. through stock acquisition
2017 August Accredited under ISO9001/2015(Company-wide)
2018 May Accredited under ISO14001/2015(Company-wide)
2023 September HOUSYOU SANGYOU INC. becomes a consolidated subsidiary.