1963 Wakayama Nainenki Kosakusho was founded in Tosa-cho, WakayamaCity to engage in the business of overhauling internal combustion engines.
1968 Wakayama Nainenki Co., Ltd. was incorporated with a capital of JPY1.5 million. An additional factory was built in haneta, Minabe-cho, for manufacturing motorcycle brake shoes.
1969 Started manufacturing die-cast clutch shoes, and supplying them as clutch assemblies for small sized engines.
1973 The capital was increased to JPY 6 million.An additional factory was built in Nishifuki, Koya-cho, for manufacturing brake shoes.
1974 The capital was increased to JPY 9 million.
1976 The Main Factory was expanded, adding the Die-casting Section. The new Minabe Factory was built, integrating the Fuki factory and the old Minabe factory.
1978 The capital was increased to JPY 10 million.
1979 The Main Factory was expanded, and the Designing and Research Section was established and enhanced.
1981 The Main Factory was expanded, enlarging the work space.The capital was increased to JPY 20 million.The Numazu Factory was built to operate as a die-casting factory.
1982 Started manufacturing rearview mirror components for automobiles.
1984 Started manufacturing compressor pistons for air conditioners.Transferred the overhaul business of internal combustion engines and automotive brakes to another company, and started operating completely as a manufacturing factory.
1985 Started the integrated manufacturing of small sized engine pistons from casting to processing in Nakanoshima, WakayamaCity. (The Nakanoshima Factory was built.)
1986 An additional factory for piston processing was built on the west side of the Main Factory premises.
1988 Shokibai Co., Ltd. was incorporated.
1989 The Head Office building was completed.
1990 The lineup of centrifugal clutches was enhanced.
1991 Acquired Yamamoto Mfg. Co., Ltd.The die-casting factories were integrated into the Main Factory.
1992 Won the Best Award (Labor Minister Award) at the Workplace Improvement Contest held by the Association of Employment Development for Senior Citizens of Labor Ministry (the current Ministry of Health, Labour and Welfare).
1994 A third sector company Winnac Co., Ltd. was jointly incorporated by WakayamaPrefecture, WakayamaCity and AcroNainen as a company to employ a large number of severely disabled people.
1995 The capital was increased to JPY 25 million, and then doubled to JPY 50 million.
1996 Received the “Superior Forward-Looking Businesses Award” from Nikkei Inc.
1997 The main store of Shokibai Co., Ltd. was built and opened in Nishitakamatsu, Wakayama City.
1999 Acquired ISO 9001 certification.
2001 The capital was increased to JPY 110 million.Shanghai Censi Automobile Parts Co., Ltd. was incorporated in Shanghai, China.
2003 The capital was increased to JPY 147.5 million.The company name was changed from Wakayama Nainenki Co., Ltd. to Acro Nainen Co., Ltd.
2004 Minabe Factory was relocated to TanabeCity, and renamed as Tanabe Factory.The clutch section was transferred from Main Factory to Tanabe Factory.
2006 Chosen as one of the “300 Energetic Small and Medium Manufacturing Enterprises” (by Small and Medium Enterprise Agency, Ministry of Economy, Trade and Industry).
2007 ACRO (THAILAND) CO., LTD. was incorporated.
2010 The factory building for ACRO (THAILAND) CO., LTD. was completed.
2013 Huzhou Shengxi Electronics & Technology Co., Ltd. was incorporated in Huzhou, China.
2015 Kiichi Katsumoto assumes office as Chairman,Masato Katsumoto as President.
2018 Fully automatic die casting piston manufacturing line completed at Tanabe factory
2018 Established Sole Proprietorship (Maanshan) Co., Ltd. in Maanshan City, Anhui Province, China.
2021 Nagano factory closed
2021 Merged with Winnac Co., Ltd., a wholly owned subsidiary. Transferred the recycled toner business to Winworks, a general incorporated association.