A disk drive is provided for restraining deterioration of the verticality of the optical axis of an optical pickup in relation to the surface of the disk when the side of the disk to be scanned for the recording and/or reproducing action is alternated from one side to the other side, in recording and/or reproducing data signals on both sides of the disk. The disk drive (1) includes a turn table (11) on which a disk D is rotatably supported, a pickup (12) for recording and/or reproducing data signals on both sides of the disk D rotated by the turn table (11), and a disk tray (31) for transferring the disk D between a recording and reproducing position which confronts the turn table (11) and a loading and unloading position at the outside of the disk drive (1). A turning movement mechanism is provided for turning the turn table (11) and the pickup (12) at once from a first position which confronts the one side of the disk D to a second position which confronts the other side of the disk D or vice versa.