On December 25, 1958, when Watanabe was a Rikkyo University student, he debuted for Japan national team against Hong Kong.

At 1968 Summer Olympics, he played 5 games and scored 2 goals against Brazil and France.

In 1979, he became an assistant coach for Japan national team under manager Yukio Shimomura.

However, just before 1982 World Cup qualification in December, he suffered a subarachnoid hemorrhage and replaced to Saburo Kawabuchi.

This biographical article related to a Japanese association football forward is a stub.