To make the sound start fast at the reproducing start time without causing a sound brake in the top of a piece of music.

Whether or not the length that the musical data are continuously recorded from a reproducing start position is a prescribed length or longer is investigated referring to UTOC information, and when it is the prescribed length or below, after the musical data of the time length (t) of an extent that the sound brake doesn't occur are written in a shockproof memory 21b, the musical data are read out from the shockproof memory in order of reproducing to be reproduced, and when it is the prescribed length or above, after the musical data of the minute time length shorter than the time (t) are written in the shockproof memory 21b, the musical data are read out from the shockproof memory in order of reproducing to be reproduced.