Myojin was born in Kobe on January 24, 1978. He joined J1 League club Kashiwa Reysol from their youth team in 1996. He played many matches as defensive midfielder from first season. He became a regular player under manager Akira Nishino in 1998. In 1999, Reysol won the champions in J.League Cup and the 3rd place in J1 League. In 2000, Reysol won the 3rd place in J1 League for 2 years in a row and he was selected Best Eleven award. However the club results were sluggish from 2002 and was relegated to J2 League end of 2005 season.