On December 25, 1958, when Miyamoto was a Waseda University student, he debuted for Japan national team against Hong Kong. He was selected Japan for 1964 Summer Olympics in Tokyo and 1968 Summer Olympics in Mexico City. Although he did not play at 1964 Summer Olympics, he played 5 games at 1968 Summer Olympics and Japan won Bronze Medal. In 2018, this team was selected Japan Football Hall of Fame. He also played at 1962 and 1966 Asian Games. He played 44 games and scored 1 goal for Japan until 1971.