Music piece data of so-called managed music pieces, each of which requires allowance of performance for each karaoke apparatus are stored in a hard disk in the same manner as music piece data of other karaoke music pieces. A ROM (20), which has stored therein key data for allowing performance of a managed music piece, is produced for each of the managed music pieces and for each of karaoke apparatuses. Performance of a managed music piece is allowed by setting a corresponding ROM (20) into a karaoke apparatus. Accordingly, a karaoke apparatus is not required to have a medium such as a CD-ROM for each of managed music pieces, and the copyright holder of a managed music piece can physically manage the number of allowed performances by way of the ROM (20).