Patent ID: 8107331

Claim:
An optical disk apparatus comprising: an objective lens that condenses, onto a uniform recording layer in an optical disk, an information light beam for recording or reproducing information in or from the optical disk on which a concentric or spiral shaped track is formed in the uniform recording layer by recording marks each representing the information and a reference light beam to be irradiated onto a reference track that has been formed on the optical disk; an optical path forming section that forms optical paths of the information light beam and reference light beam which are allowed to enter the objective lens such that a distance between the objective lens and a focal point of the reference light beam and a distance between the objective lens and a focal point of the information light beam are equal to each other in an optical axis direction of the information light beam and that the focal points of the information light beam and reference light beam are away from each other in a radius direction of the optical disk by a distance corresponding to a total width of a predetermined number of tracks; and a position control section that controls a position of the objective lens so as to focus the reference light beam onto the reference track, wherein lead-in marks are previously formed in the recording layer of the optical disk, the lead-in marks indicating positions, in the optical axis direction of the information light beam, of a plurality of laminated mark layers formed by the recording marks and when a position near the lead-in mark is set as a target position, the position control section sets the lead-in mark as the reference track and focuses the reference light beam onto the lead-in mark.