This study aimed to investigate the reason of adolescent's school violence. The subjects of the experiment are middle school students. Collected data were analyzed using a multiple regression. The results were as follows: first||| the experience of school violence is different in gender and it is discovered that occurrence rate of male adolescent's emotional and physical violence was more higher than female adolescent. Second||| in case of male adolescent||| self-control is affected by emotional violence. Third||| emotional violence of female adolescent is affected from parental monitoring||| friends attachment||| school attachment||| and self-control. Finally||| physical violence of female adolescent is affected from devotion and self-control.