The purpose of this study was to analyze, through exploratory factor analysis, the perceptions of music therapists towards therapeutic factors inherent in music. Those perceptions were then compared with those of non-experts. In order to develop the questionnaire items for the main survey, related literatures were reviewed and an open questionnaire survey was implemented for music therapy experts with five years or more of clinical experience. The questionnaire items were then modified by researchers and given in the main survey to members of the Korean Music Therapy Association and non-experts to evaluate the importance of the factors. The results were as follows: First, five factors were derived through factor analysis to represent the therapeutic factors of music : pleasure/aesthetic experience factor, cognition/behavior factor, emotion/insight factor, physical/sensory factor, and social/group factor. Second, the evaluations of each factor among therapists were found to be not significantly different by individual perspective but by the classification of music versus non-music major: non-music majors perceived the pleasure/aesthetic experience factor and emotion/insight factor as more important than music majors did. Third, non-experts perceived the pleasure/aesthetic experience factor as more important than music therapists did, and also showed statistically significant differences in their perception of cognition/behavior, emotion/insight, and social/group factors related to the therapeutic goals. This study is meaningful in that it experimentally examined and confirmed the therapeutic factors of music.