An apparatus for recording and/or reproducing information on and/or from a magneto-optical
disk including an optical head for projecting a laser beam onto a magneto-optical
disk and receiving the laser beam reflected by the disk, an up-down block arranged
movably between a lower position and an upper position, an up-down motor for moving
said up-down block up and down, a turntable for supporting the disk and a spindle
motor secured to said up-down block and having a driving shaft coupled with said
turntable for rotating the turntable, a position detecting device for detecting
a position of said up-down block to derive a position signal when the up-down block
is driven into the upper position, a rotation detecting device for detecting a
rotation of said optical information record disk to derive a rotation signal when
the optical information record disk is rotated at a predetermined revolving speed,
and a control device for initiating a focus control for moving said objective lens
and turntable relative to each other in accordance with said position signal and
rotation signal.