The purpose of this study was to investigate the process of individual music therapy and to classify psychological and behavioral change emerged in music therapy sessions for adolescent with internet addiction. The individual music therapy sessions were done 52 sessions, once in a week, from April, 2008 to June, 2009, on Hyun-Woo(pseudonym), a 14 year old boy with internet addiction. Hyun-Woo was middle school student and diagnosed with social skill deficit and internet addiction in psychological test and Korea internet addiction test(K-scale). This case study focused on how Hyun-Woo changed his self-recognition and expressed self-regulation included anger management and integration in music. Also, this study explored how Hyun-Woo got over difficulties in personal relation and how music played important role in this process. On analyzing his musical and non-musical reaction, it was discussed how music had meaningful effect on his way of thinking and behavior, and importance of individual music therapy for an adolescent with internet addiction. key word : internet addiction, self-recognition, anger management, individual music therapy