PURPOSE: To make the device simple in structure, low in cost and improved in stability and accuracy of operation by driving a turntable and a tray by single drive motor.

CONSTITUTION: When the turntable 21a is rotated, the forward/backward rotatable drive motor 21 is rotated forward, and the turntable 21 is rotated forward through respective gears 22, 23, 24. At this time, a pinion 24b of a two steps gear 24 is in the state that it isn't engaged with the rack 30a of the tray 30, and the two steps gear 24 is raced. When a disk is exchanged, the drive motor 21 is rotated counterclockwise by switch operation, and the two steps gear 24 is rotated counterclockwise through respective gears. At this time, an engagement projection part 25c of an operation lever depresses downward the guide projection part 30b of the tray 30 to move the tray 30 downward. Then, the rack 30a is engaged with the pinion 24b of the two steps gear 24, and the tray 30 is transferred forward, and the disk is exchanged. Thus, the constitution is simplified, the cost is reduced, and the stable and sure operation is obtained.