Data is recorded in a first part in accordance with a signal format equivalent to that of an existing CD at the lower limit of an allowable value of a track pitch and the lower limit of linear velocity, so that data can be recorded in the first part for the maximum regeneration time. An existing CD reproducing apparatus can reproduce the audio data recorded in the first part. Compressed and encrypted audio data is recorded in a second part at a single density or at a double density. The single density represents a recording density equivalent to that of an existing CD and the double density represents a density two times larger than the single density. Audio data recorded in the second part is charged when reproduced to protect copyrights. The format of the data recorded in the second part uses the format of a CD-ROM.