A cleaner (C.sub.1) for an magneto-optical disk device includes a cartridge (4), a disk (1), an adhesive sheet (2) stuck to the disk (1), a clamping disk (3), and a shutter (5). The clamping disk (3) is stored rotatable in the cartridge (4), and the disk (1) is fixed to the cartridge (4) at a position apart from the clamping disk (3). By this means, it becomes possible to safely clean an optical head (17). Also, dust can be prevented from scattering to the magneto-optical disk device (P.sub.1).