Kojima was born in Maebashi on January 17, 1966. After graduating from Doshisha University, he joined Japan Soccer League club Fujita Industries (later "Bellmare Hiratsuka") in 1988. In 1992, Japan Soccer League was folded and the club joined new league, Japan Football League. The club won the champions in 1993 and was promoted to J1 League from 1994. He became a regular goalkeeper from 1994. The club won the champions in the 1994 Emperor's Cup. At the end of 1998, Bellmare released their main players including Kojima as well as Wagner Lopes, Hong Myung-bo, Kazuaki Tasaka and Yoshihiro Natsuka due to their financial problems. Kojima moved to Avispa Fukuoka in 1999. The club was relegated to J2 League end of 2001 season. In 2002, he moved to his local club Thespa Kusatsu which club played in Prefectural Leagues. The club was promoted to Regional Leagues in 2003, Japan Football League in 2004 and J2 League in 2005. He retired end of 2005 season.