An automatic accompaniment apparatus includes: a storage unit for storing accompaniment style data including basic accompaniment data for automatic accompaniment and replacement accompaniment data to be reproduced in place of the basic accompaniment data; and a reproducing unit for reading the stored accompaniment style data and reproducing the read accompaniment style data, the reproducing unit reproducing the read accompaniment style data by replacing a portion thereof with the replacement accompaniment data. The automatic accompaniment apparatus can generate derivative accompaniment style data from original accompaniment data with ease.