Abstract: An optical disk drive apparatus, for data or information disks of which the data or information are able to record or playback on each of the recording tracks, comprises an optical rotary pick-up head actuator for both seeking and following to the recording track to read or write data signals by a light beam. The light beam is injected along the axis of rotation of the optical rotary pick-up head actuator; guided through a stick-shaped prism in cantilever form which is fixed by one side on the optical rotary pick-up head actuator and is unsuspended by the other side; and focused upon the recording surface of the disk through an objective lens which can be rotatively moved and controlled with the optical rotary pick-up head actuator in the direction to seeking the tracks. An reflective light beam from the recording surface of the disk is guided in the reverse order and is taken out from the center axis of rotation.