On January 5, 1955, when Iwabuchi was a Keio University student, he debuted for the Japan national team against Burma. In June 1956, at 1956 Summer Olympics qualification against South Korea, he scored a goal. After the qualification, Japan won the qualification to 1956 Summer Olympics in Melbourne by the drawing of lots. In November, he was selected Japan for 1956 Olympics. He also played at 1958 Asian Games. He played 8 games and scored 2 goals for Japan until 1958.