This study explores how Korean pop (K-pop) dance therapy influences the mental health of the female juvenile delinquents in a reformatory. 20 female students were recruited in J reformatory in Korea. They took K-pop dance therapy during 2 hours, once a week, for 3 months. This research is based on qualitative research methods - our observations of and interviews with the participants, and their self-reports. The results are as follows. First, the K-pop dance therapy helped them to relieve their stress. Especially, the distinctive features of stress-violence and abuse were remarkably decreased. Second, the program helped the participants to develop self-confidence. Third, they exhibited strong ties with members, which produce better teamworks and interactions. As a result, the social skills of the participants were improved. Therefore, this K-pop dance therapy could contribute to mental rehabilitation and correction in education field.