is a Japanese politician of the Liberal Democratic Party, a member of the House of Representatives in the Diet (national legislature).
After graduating from Aoyama Gakuin University, Yamaguchi went to Paris to study at ParisÃÂ IV University. During his stay there, he resolved to contribute to Japan as a politician. Yamaguchi was elected to the first of his four terms in the assembly of Tokushima Prefecture in 1975 and then to the House of Representatives of Japan for the first time in 1990.
In February 2026, Yamaguchi became chairman of the Committee on Rules and Administration in the House of Representatives.
Yamaguchi is affiliated with the conservative organization Nippon Kaigi.