A format of a recording medium suitable for a larger capacity, a higher transfer rate, and integration of pits/lands/grooves is provided. In a first method, in a recordable and reproduceable area, a twin-track structure of lands/grooves is configured such that tracks on which lands become recording tracks and tracks on which grooves become recording tracks form a double spiral. In a read-only area, pits are arrayed such that tracks in the radial direction of the disk are formed in a data area. In a second method, in a recordable and reproduceable area, a land/groove-alternate track structure is configured such that grooves become data recording tracks in the circular track next to the circular track in which lands become data recording tracks, and lands become data recording tracks in the next circular track. In the read-only area, pits are arrayed such that tracks in the radial direction of the disk are formed in the data area.