| November 1968 | Began general processing and regenerative coloring as a private business. |
| March 1969 | Eikou Bussan inc. was founded with a capital of two million yen. |
| November 1970 | The company was renamed Eikou Bussan Co., Ltd, with a capital of two million yen. Designated by Idemitsu Petrochemical Co., Ltd. as a cooperative coloring plant. |
| February 1973 | Founded Eikou Co., Ltd. with a capital of 15 million yen. |
| June 1973 | Tsuneyuki Ueda assumed the presidency of the company. |
| June 1978 | Designated by CALP Corporation as a cooperative coloring plant. Expanded the business field from general coloring into composite material processing. |
| October 1982 | The head office's plant was constructed. All business operations and production were transferred to it. |
| November 1983 | Increased the capital to eight million yen. |
| April 1985 | Introduced a computer color matching system. |
| November 1986 | The head office's plant was enlarged. The enlarged area began operation as a transparent parts plant. |
| September 1987 | The Kanto Plant began operation as a composite material processing plant covering the Kanto area. |
| April 1988 | The Nagoya Plant began operation. |
| January 1991 | The head office building was completed. |
| October 1994 | Increased the capital to ten million yen. |
| March 1995 | The Shizuoka Plant began operation. |
| May 1997 | Siam Eikou Co., Ltd. was founded. |
| August 1997 | The Kanto Plant was integrated into the Shizuoka Plant. |
| December 2000 | Acquired an ISO 9002 certification. |
| October 2001 | Increased the capital to 30 million yen. |
| March 2002 | The third plant was made the Recycling Plant through integration with the Nagoya Plant. |
| January 2003 | Acquired an ISO 9001 certificate. |
| May 2003 | Founded Shanghai Eikou Co., Ltd. |
| July 2003 | Acquired a Green Partner certificate. |
| November 2003 | Operations of Founded Shanghai Eikou Co., Ltd. Plant were launched. |
| November 2005 | Increased the capital to 50 million yen. |
| March 2006 | Shanghai Eikou Co., Ltd. acquired an ISO 9001 certification. |
| April 2006 | The head office's building for testing and development was completed. |
| July 2008 | Ended joint venture with Siam Eikou Co., Ltd. |
| September 2008 | Eikou Co., Ltd. was established. |
| November 2008 | Acquired the Shizuoka Dispatch Center site |
| January 2009 | Acquired an ISO 14001 certification. |
| October 2009 | Operations of the Eikou Co., Ltd. Plant were launched. |
| February 2011 | Eikou Co., Ltd. acquired an ISO 9001 certification. |
| March 2012 | Shanghai Eikou Co., Ltd. acquired an ISO 14001 certification. |
| June 2012 | Shanghai Eikou Co., Ltd.'s plant was enlarged. |
| January 2014 | EIKOU CO., LTD. Warehouse was completed. |
| December 2014 | Extruder Line for small lot was enlarged. |
