An optical disk physical has a recording region divided into zones, each zone including physical tracks adjacent to each other. An integer number of sectors, are provided in each physical track. The angular recording density is higher in the more outward zones such that the linear recording density is substantially constant throughout the recording region, and logical tracks are formed of a predetermined number of sectors, independent of the physical tracks. The conversion between the logical track and sector addresses read from the disk and the linear logical addresses supplied from a host device is easy. The addresses written in headers of the sectors in the logical track in which data are actually recorded, including substitute sectors used in place of defect sectors, are preferably consecutive to further facilitate the conversion between the logical track and sector addresses read from the disk and the linear logical addresses supplied from the host device. Each of the zones can be set to serve as any of the different types of recording area, independently of other zones.