Kosaku Masuda (増田 功作, Masuda Kōsaku, born April 30, 1976) is a Japanese football manager and former player who is the manager of J2 League club Tokushima Vortis.
After graduating from high school, he played for Bolivian and Brazilian clubs.
In 1998, he returned to Japan and joined J1 League club Verdy Kawasaki.
In 1999, he moved to new club Yokohama FC in Japan Football League.
This biographical article related to a Japanese association football midfielder born in the 1970s is a stub.