Data is recorded in a first part PA1 in accordance with a signal format same as that of an existing CD at the lower limit (1.5 .mu.m) of an allowable value of a Wreck pitch and the lower limit (1.2 m/sec) of a linear velocity. As a result, the data for the maximum regeneration time (74.7 min) can be recorded in the first part PA1. An existing CD reproducing apparatus can reproduce the audio data recorded in the first part PA1 with no problem. Moreover, compressed and encrypted audio data is recorded in a second part PA2 at a single density or a double density. The single density represents a recording density same as that of an existing CD and the double density represents a density two time larger than the single density. Furthermore, the audio data recorded in the second part PA2 is charged when reproduced in order to protect copyrights. The format of the data recorded in the second part PA2 uses the format of a CD-ROM.