A compatible disk device comprising a holder arm (112) for holding a second turntable (7) that transmits torque to a second disk that is not received in a cartridge, a sub-base assembly (111) by which a clamper arm (113) that holds a clamper (10) for clamping a first disk, which is received in a cartridge, between it and a first turntable (5) is held such that the clamper arm is vertically swingable with respect to the surface of a base (100) and turnable on a plane along the surface of the base (100), and a mode switching member (130) reciprocatingly disposed on the base (100) for switching between first and second disk reproducing modes.
