Masahiro Usui is a Japanese actor and the second-youngest of the acting group D-BOYS, produced by Watanabe Entertainment. Usui joined D-BOYS through the 4th D-BOYS open audition, held on May 28, 2007. Winner of the audition's Grand Prix, Usui was officially added to the group on December 30, 2007, after making his entertainment debut was on the TV Tokyo comedy series ChocoMimi.