Abstract: A connecting member connects a pair of holder plates toward the end of the holder plates at the recessed end in the direction in which the disk is inserted. By forming the holding member holding disks using three pieces, there is less deformation causes by high temperatures compared to integrally formed units. Also, since this connecting member only serves to connect the pair of holder plates, a thin rod-shaped connecting bar can be used. This allows the clearance between the disks held toward the back of the device and the rear panel to be minimized, thus contributing to a reduced depth dimension for the device.