Abstract: A disk-changing device is disclosed which is able to house a plurality of disk-shaped recording media, and is capable of miniaturization. The recording media are arrayed in one orientation, and the play-back mechanism selects one desired disk, takes it out and performs a predetermined operation such as play-back on the data recorded on the disk. The play-back mechanism is constructed to be capable of movement between the housing positions of the recording media. This movement is based on a plurality of pairs of plate cams which are provided on the inside of the chassis of the device and are able to move reciprocally, and on cam followers which are provided in the play-back mechanism and are inserted into the cams of the plate cams. The shape of the cam is a back-switching stepped shape, with the result that it is constructed in such a way that the amount of movement of the play-back mechanism in the horizontal direction is small. Consequently, the volume of the device as a whole can be kept low.