| 1937 | ： | Founder KEiji Maezawa estabishes Showa Manufacturing Co.,Ltd. in Tokyo. Begins selling various mashinery and equipment for water supply. |
| 1947 | ： | Reorganized and incorporated as Maezawa Valve Industries,Inc. |
| 1950 | ： | The Kawaguchi Plant is established in Saitama Prefecture.Begins integrated manufacturing system of valves and plugs for water works. |
| 1954 | ： | The Kawaguchi Plant obtains certification as an authorized JIS factory. |
| 1961 | ： | Satte Plant is constructed in Saitama Prefecture.Begins integrated manufacturing system of products ranging from casting to machinery. |
| 1973 | ： | The company changes its name to Maezawa Industries,Inc. |
| 1986 | ： | Moved and integrated two plants into the Satte Plant,which was reorganized as the Saitama Plant for the improvement and expansion of the production system. |
| 1987 | ： | Maezawa Industries,Inc.is registered as an over-the-counter stock with the Japan Securities Dealers Association. |
| 1988 | ： | Established the Central Laboratory |
| 1998 | ： | Aqua Tech Center is constructed in Kawaguchi,Saitama Prefecture. Industrial Environment Division is established as a division specializing in industrial wastewater treatment. |
| 2009 | ： | The headquarters and the headquarters function were consolidated in Aqua Tech Center. |
