Abstract: The present invention is provided with a first and second spindle at respective initial positions spaced apart by a predetermined distance and disposed linearly at both sides of inspection positions where the spindles are set for disk inspection, a disk inverting mechanism is provided at either the front side or the back side of the inspection position, at the same time when a disk fitted to the first spindle is transferred to the inspection position, a disk fitted to the second spindle is returned from the inspection position to own initial position, and at the same time when a disk fitted to the second spindle is transferred to the inspection position, a disk fitted to the first spindle is returned from the inspection position to own initial position, and the disk fitted to the first spindle which is returned to the own initial position is delivered to the disk inverting mechanism, thereby an inverted disk is fitted to the second spindle.