In an optical disc apparatus, a minimum jitter value is established from each
jitter value measured in correspondence to a successively changed servo constant,
and multiplied by a prescribed ratio so as to set a jitter threshold value. Servo
constants corresponding to at least two jitter values substantially equal to the
jitter threshold value is established, and an optimum servo constant is set based
on this minimum of two servo constants. By doing this, it is possible to quickly
and accurately detect the optimum servo constant, and achieve good servo adjustment.
