An optical disk apparatus includes an optical pickup head (PUH) which
outputs a laser beam through an objective lens. When a control unit
receives an instruction to halt data read-out from an optical disk, the
control unit moves the PUH to a predetermined position, stores a focus
driving voltage corresponding to a position of the objective lens in a
memory unit, and halts the output of the laser beam from the PUH. When
the control unit receives an instruction to resume the data read-out, the
control unit resumes the output of the laser beam from the PUH, starts a
focus search on the basis of the focus driving voltage that is stored in
the memory unit, moves the objective lens in a direction toward the
optical disk, and achieves focus adjustment.