He played for Japan national team.
Miyaji played for Osaka SC many Japan national team players Yoshimatsu Oyama, Uichiro Hatta, Sakae Takahashi and Kiyonosuke Marutani were playing in those days.
In May 1925, Miyaji was selected Japan national team for 1925 Far Eastern Championship Games in Manila.
But Japan lost in both matches (0-4, v Philippines and 0-2, v Republic of China).
This biographical article related to a Japanese association football midfielder is a stub.