An information recorded medium wherein a program for a computer in a music recording/reproducing system which controls reproducing of a plurality of pieces of music data recorded on a first recording medium and controls reproducing of a plurality of pieces of music data recorded on a second recording medium, is recorded so as to be read by the computer, the program makes the computer function as:
- when a predetermined a piece of music data is reproduced from the first recording medium, checking out the piece of music data and at least one piece of music data to be subsequently reproduced, from the first recording medium to the second recording medium, and
- when the reproducing of the piece of music data is ended, checking in the piece of music data from the second recording medium to the first recording medium, and then newly checking out a piece of music data to be reproduced after said at least one piece of music data, from the first recording medium to the second recording medium.