PURPOSE: To enable information to be recorded into and reproduced from both surfaces of a magneto-optical disk.

CONSTITUTION: A laser beam which is output from a laser diode 11 is separated by a beam splitter 13 and one laser beam is focused and emitted to a lower disk 1a through an objective lens 42. Also, the other laser beam is focused to an upper disk 1b through an objective lens 52. Focusing coils 43 and 53 are driven independently at movable portions 4 and 5. On the other hand tracking coils 44 and 54 and seeking coils 45 and 55 are driven by the same signal.