After retirement, Miyamoto became a manager for Honda in 1983 and managed until 1989. In January 1989, he also managed for the Japan national futsal team for 1989 Futsal World Championship in Netherlands. In 1992, he signed with Kashima Antlers joined new league J1 League. In 1993, he led the club to won the 2nd place at J1 League and Emperor's Cup. he resigned in June 1994. He also managed Shimizu S-Pulse in 1995.