An optical disk (1) which comprises a track groove (402) on which positional information indicating a physical location on the track groove is represented by a wobble shape of the track groove, wherein the optical disk includes a plurality of positional information units (404) that are arranged on the track groove, and wherein each said positional information unit (404) includes: a precision positioning mark section (405), and a positional information section (406), the positional information section (406) represents the positional information by a combination of wobble patterns selected from multiple types of wobble patterns that have been defined so as to correspond to respective signal waveforms that rise and fall mutually different, and the precision positioning mark section (405) is provided ahead of the positional information section (406), and includes an identification mark for use in precision positioning.