| April 1975 | Elected to the Aomori Prefectural Assembly
（re-elected in 1979） |
| December 1983 | Elected to the HR（House of Representatives）
（37th General Election） |
| July 1986 | Elected to the HR（House of Representatives）
（38th General Election） |
| February 1990 | Elected to the HR（House of Representatives）
（39th General Election） |
February 1990
- November 1991 | Deputy Chief Cabinet Secretary |
| July 1993 | Elected to the HR（House of Representatives）
（40th General Election） |
August 1995
- January 1996 | Minister of State, Director-General of the Environment Agency |
| October 1996 | Elected to the HR（House of Representatives）
（41st General Election） |
October 1999
- June 2000 | Chairman, Standing Committee on Rules and Administration, House of Representatives |
| June 2000 | Elected to the HR（House of Representatives）
（42nd General Election） |
July 2000
-December 2000 | Minister of Education, Science, Sports and Culture / Minister of State for Science and Technology |
| September 2002 | Minister of Agriculture, Forestry and Fisheries |
