Ihara was born in Koka on September 18, 1967. After graduating from University of Tsukuba, he joined Japan Soccer League club Nissan Motors (later "Yokohama Marinos", "Yokohama F. Marinos") in 1990. The club won the 2nd place in 1990/91 and 1991/92 season. He was also selected Best Eleven in 1991/92. In 1992, Japan Soccer League was folded and the club joined new league J1 League. The club won the champions in 1995 season. He was selected Best Eleven for 5 years in a row (1993-1997). He played 267 matches for the club until 1999. Toward the end of his career, he played for Júbilo Iwata (2000) and Urawa Reds (2001-2002).