Effects of music on emotional responses have been investigated from two viewpoints independently; the musical mood and the musical preference. However, since previous studies could not control both musical mood and preference to examine the relaxation effect of music, there was no clear result which factor was dominantly affected on relaxation, musical mood or preference. The purpose of the present study was to investigate the effects of the musical mood and preference on relaxation. Fifty-four undergraduates, who evaluated presented musical pieces favor and/or unfavor, served as subjects. Musical pieces used in this experiment were 3rd movement of Mahler's 6th symphony as sedative and 4th movement of Tchaikovsky's 4th symphony as excitative. All subjects listened to both pieces. As the result, subjective dimensions of relaxation and refreshed feeling were affected by only a musical mood; a sedative music was evaluated more relax and less refreshing than an excitative one. On the other hand, subjective tension was decreased by a sedative music or a preferred music. For physiological responses, heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP) showed the only effect of musical mood which an excitative music increased physiological responses. Respiration rate (RR) was also affected by both musical mood and preference, in which respiration rate decreased by a sedative piece and/or a preferred one. These results indicated that musical mood was a dominant factor to decrease psychological and physiological arousal more than musical preference.