On May 21, 1995, Morishima debuted for the Japan national team against Scotland. In 1996, played at 1996 Asian Cup. At 1998 World Cup qualification in 1997, Japan won the qualify for 1998 World Cup first time Japan's history. At 1998 World Cup, he got 11 minutes as a substitute against Croatia. In 2000, he played at 2000 Asian Cup. he played 5 matches and Japan won the champions. In 2001, he played at 2001 Confederations Cup. He played in all 5 matches and Japan won the 2nd place. At the 2002 World Cup he got three games as a substitute, scoring after two minutes in the game against Tunisia. He played 64 games and scored 12 goals for Japan until 2002.