A disk transfer device including a disk tray for holding a disk during the disk transfer action and a tray driving mechanism for driving the tray forward and backward between a first position which is the retracted location of the tray corresponding to a turntable in a disk drive and a second position which is the loading and unloading location of the disk outwardly of the disk drive. The disk tray is provided with a large diameter support region and a small diameter support region which is stepped down by a predetermined distance from the large diameter support region. A plurality of claws capable of engaging with the peripheral edge of the lower side of a small size disk are provided on the outer periphery of the small diameter support region. When the small size disk held and pinched between the clamper and the turntable is unloaded from the turntable, the peripheral edge climb over the claws, thereby, the disk is moved toward the turntable and released from its held state between the clamper and the turntable.