The reproducing of the MP3 part is started from a first reproducing start position that is positioned prior to a second pointed reproducing start position. In this case, this MP3 part is mute-reproduced in a period that extends from the first reproducing start position to a timing corresponding to the second reproducing start position. Then, the mute is canceled when progress of the MP3 part arrives at a timing corresponding to the second reproducing start position, and at the same time the reproducing of the MIDI part is started.