PURPOSE: To record a CLV(constant linear velocity) disk with double density.

CONSTITUTION: Subspots 6 and 7 are disposed at positions deviated from a main spot 5 by 1/2 track pitch, and a tracking error signal is obtained from a push-pull signal obtained from the main spot, and also its polarity is changed, so that tracking control is performed on the main spot to be at the center of a group 1 or the center of a land 2. Then, when the main spot is controlled to be at the center of the group, address information is read out of the push-pull signal from the main spot, and when the main spot is controlled to be at the center of the land, the address information is read out of the push-pull signal from the subspot.