Patent ID: 7646689

Claim:
A disk discriminating method of discriminating the kind of an optical disk, comprising the steps of: measuring an amplitude of one of a focus error signal and a tracking error signal several times, wherein the focus error signal is generated based on a focus drive signal giving disturbance to a pickup in a focus direction and the tracking error signal is generated based on a tracking drive signal giving disturbance to the pickup in a radial direction of the optical disk; comparing the measured amplitude of one of the focus error signal and the tracking error signal with a threshold value, after the several times of measuring; and discriminating the kind of the optical disk according to the result of the comparison, wherein the discriminating step comprises determining whether to change an amplification gain of one of the focus error signal and the tracking error signal based on the result of the comparison, and changing the amplification gain of one of focus error signal and the tracking error signal based on the threshold value used for the comparison if it is determined to change the amplification gain, and discriminating the kind of the optical disk based on the changed amplification gain.