The rate of teenagers' misconduct and delinquency has been increased and those have been a big social issue these days. The purpose of this study was to reduce their aggression and depression causing their misconduct and delinquency as a consequence of improving children's self-concept. For this, we carried out Group Art Therapy Program for high-grade students in elementary school. The research design was the pretest-posttest control group design. The subjects were selected 5 students as an experimental group and 5 students as a control group. Then the program was applied to these groups from December in 2002 to March in 2003. The results were tested by t-test method and the hypotheses were mostly accepted at the .05 of α-level. The results and discussion of this study were as follows: First, the level of self-concept of experimental group was significantly higher than that of the control group in the post-test, and thus this difference could be meaningful statistically. Secondly, the level of aggression of experimental group was significantly lower than that of the control group in the post-test, thus this difference could be meaningful statistically. Thirdly, the level of depression of experimental group was lower than that of the control group in the post-test, thus this difference could be meaningful statistically. Finally, as the results of each session analysis, the level of aggression and depression of experimental group was significantly lower than that of the control group in the post-test. Therefore, the program was ascertained to be effective. In the view of the results so far achieved, we can recognize self-concept improvement art therapy program has influence on reducing children's aggression and depression as a consequence of improving their self-concept.