The present study explores the effects of music on the performance of vigilance task. ECG and SCL were recorded on 40 students during periods of (1) baseline, (2) pre-music, (3) music (control/musical stimulus), and (4) post-music. Twenty subjects, who were assigned to the forward replay music group, participate in the control and the music sessions. They listened to ordinary music during the music period in the music session. The other twenty subjects were assigned to reverse replay music group. They listened to the reverse playback of music, using in the forward replay group. Two types of musical stimuli increased the hit ratio in comparison with control session and maintained the hit ratio at a high level. This tendency was clear in forward replay music rather than in reverse replay music. Similar changes of performance, two types of musical stimuli increased SCL and HR. However, the positive changes of scores on mood scale (increased in vigor vs decreased in depression and fatigue) were found in only the forward replay group. These findings indicated that the music facilitated the vigilance peformace. Furthermore, it is implied that the effects on music on vigilance consisted of two functions, one of which increases vigilance level depending on quantity of musical stimuli, and the other regulates the subjects' mood in a positive direction depending on the connotative meaning of musical stimuli.