Abstract: There is provided an optical disk device in which no deterioration in playability at resisting vibrations in a disk servo system is generated by inadvertently recognizing it is in a non-vibrating state irregardless of it is in a vibrating state in a disk servo system. By providing two threshold values of a threshold value for detecting a vibration state during a non-vibration state and a threshold value for detecting the non-vibration state during the vibration state, or by performing a filtering to an error signal using a filter having filter constants different between during the vibrating state and during the non-vibrating state, it is possible to prevent erroneous recognition of the non-vibration state and thereby to prevent deterioration in playability of the disk servo during resisting earthquake.

Abstract: A relative traveling speed detector receives a focus error signal and detects a traveling speed of a pickup relative to a disk. A drive mode determining unit determines a drive mode of the pickup according to the detected relative traveling speed. A drive output generating means generates a focus drive signal for driving the pickup according to the drive mode. The disk drive device is thus capable of reducing the time required to restore a focus servo operation.