Then he was appointed by Prime Minister Ryutaro Hashimoto as the minister of finance on 27 January 1998. Matsunaga replaced Hiroshi Mitsuzuka as finance minister. Mitsuzuka was forced to resign due to corrupt behaviour of the officials at the ministry. In April 1998, Matsunaga reported that 112 ministry officials would be punished due to their excessive entertainment from banks, brokerage firms and insurers under their supervision. Matsunaga's term as finance minister was short lived, and he resigned on 30 July 1998, replaced by Kiichi Miyazawa, another veteran LDP politician.
