Performance information of a music performance executed by a user is received, and temporarily stored into a buffer for each given time period. The performance information is recorded into a recording section in response to a recording instruction by the user. Second performance information having a definite time period is reproduced repeatedly, and the user ad-libs a desired musical performance while listening to the repeatedly reproduced tones of the second performance information. The given time period is set to coincide with the definite time period of the second performance information. Temporarily-stored performance information for the given time period is recorded in one of a plurality of recording tracks. In response to a plurality of user's recording instructions, a plurality of different segments of performance information for the given time period are recorded into respective ones of the recording tracks, and these different segments are reproduced repeatedly in synchronized fashion.