An optical disk comprising a substrate 4, and a plurality of tracks 269 to 273 formed on the substrate 4, wherein the plurality of tracks 269 to 273 include groove tracks 270, 272 consisting of a plurality of grooves mutually space apart by a fixed space, and land tracks 269, 271, 273 consisting of areas between the groove tracks, wherein the borders 14, 15 between the groove tracks and the land tracks represent information using the waveforms from their wobbling patterns, wherein the period of the wobbling waveforms of the borders 14, 15 are constant on each border, but the wobbling waveforms of the opposite portions of the borders across the track are shifted in phase by a predetermined phase difference.