| 1951 | Entered the Ministry of Foreign Affairs (MOFA) |
| 1967 | First Secretary, Embassy of Japan in Washington, D. C. |
| 1971 | Counsellor, Permanent Mission of Japan to International Organizations in Geneva |
| 1973 | Director, Press Div., Information and Cultural Affairs Bureau |
| 1978 | Counsellor in Charge of Multilateral Trade Negotiations |
| 1979 | Consulate-General of Japan in Honolulu |
| 1980 | Resigned from MOFA |
| 1980 | Elected to the House of Councillors (HOC) |
| 1983 | Parliamentary Vice-Minister for Ministry of International Trade and Industry |
| 1986 | Elected to the HOC (2nd Term) |
| 1987 | Chairman, Committee on Commerce and Industry, HOC |
| 1988 | Director-General, International Bureau, LDP |
| 1991 | Chairman, Committee on Education, HOC |
| 1992 | Elected to the HOC (3rd Term) |
| 1993 | Deputy Secretary-General, LDP |
| 1996 | Chairman, Policy Deliberation Commission, LDP |
| 1997 | Minister of State, Director-General of Environment Agency |
| 1997 | Chairman of the third Conference of Parties of the United Nations Framework Convention on Climate Change (UNFCCC) |
| 2000 | Elected to the House of Representatives (HOR) |
| 2000 | Chairman, Special Committee on the Global Environment, LDP |
| 2001 | Chairman, Special Committee on Okinawa and Northern Territories Affairs, HOR |
| 2002 | Minister of the Environment |
| (As of Feb. 2002) |
