He played many matches as defensive midfielder in 2001 season and Marinos won the champions in 2001 J.League Cup.

He became a regular player as right side midfielder from summer and Marinos won the champions J1 League.

He was given number "3" shirt, which Tanaka's teammate at Marinos, Naoki Matsuda wore.

Tanaka played as regular player and won the 2nd place and was promoted to J1 first time in the club history.

On August 9, 2006, Tanaka debuted for Japan national team against Trinidad and Tobago.