Purpose: The purpose of this study is to clarify mediating effects of self-concept on mental health of children and adolescents who fell victim to violence. Methods: A survey was conducted on 4th, 5th, and 6th graders from 2 elementary schools and 1st, 2nd, and 3rd year students from 3 middle schools (n=2,391). Data were analyzed using descriptive statistics and AMOS. Results: The mean scores of mental health and self-concept in the subjects were 4.5 and 184.9 respectively. The rate of poor mental health in students who had fallen victim to violence was more than twice as high as that in students who had never experienced it. The self-concept of students who experienced violence had a tendency to decline. Violence experience and self-concept accounted for 47.7%(43.0% for boys and 53.4% for girls) of the changes in mental health. The indirect mediating effects of self-concept were significant. Conclusion: Based on the findings, the following is suggested. Schools should offer a self-concept improvement program for students with a distorted self-concept caused by falling victim to violence. It could help such adolescents have a positive self image and improve their mental health.