| 1899 | Aug | Established |
| 1933 | Dec | Corporation as "Unozawa-gumi Iron works, LTD." |
| 1962 | Nov | Capital increased to 100,000,000 yen. Listed on the Tokyo Stock exchange Part 2. |
| 1972 | Jan | echnical assistance agreement from Rader Company in USA.
(Material handling) |
| 1974 | Nov | Capital increased to 300,000,000 yen. |
| 1975 | Nov | Capital increased to 510,000,000 yen. |
| 1977 | Feb | The laboratory newly established in Tamagawa Factory. |
| 1977 | Sep | Integrated of Tamagawa & Shibuya factory. |
| 1984 | Mar | Unozawa-Tokyu Building constructed. |
| 1987 | Feb | Business cooperation and Technical support to Stokes vacuum, Hick Hargreaves & Hibon S. A. (Dry vacuum pump) |
| 1992 | Jan | Technical assistance agreement from Gerike in Swiss. |
| 1992 | Dec | Capital increased to 785,000,000 yen. |
| 1995 | Aug | Technical transfer to ACC in India.
(Rotary blower) |
| Dec | 12ŒŽ | Integrated of Head office & Tamagawa factory. |
