On June 15, 1997, Mochizuki debuted for the Japan national team against Turkey. he played at 1999 Copa América and 2000 Asian Cup. At Asian Cup, he played in 4 games and scored the winning goal in Final, against Saudi Arabia. Japan won the match (1–0) and won the champions second time. He played 15 games and scored 1 goal for Japan until 2001.