A disk drive apparatus includes: head means for performing laser
irradiation to and detection of reflected light from an optical disk
recording medium and having a focus bias mechanism and a spherical
aberration correction mechanism; focus bias means for driving the focus
bias mechanism to add a focus bias to a focus servo loop; spherical
aberration correction means for driving the spherical aberration
correction mechanism based on a spherical aberration correction value;
evaluation value creating means for creating an evaluation value based on
reflected light information obtained by the head means; adjustment means
for adjusting the focus bias and the spherical aberration correction
value; and control means for determining whether data is written on at
least one track of the tracks adjacent to an adjustment use range on the
recording medium and controlling an adjustment operation on the focus
bias and the spherical aberration correction value by the adjustment
means based on the determination result.