An optical disc consists of a base plate, a reflective thin layer, and a protective thin layer. The optical disc has sample mark area (32) having two sample marks (10, 11), one (10) of which is off-set one side of a track, another (11) of which is off-set another side of a track. These sample marks are produced by an injection molding with replica technique. At the time of the injection molding, additional pressure moves soft injected plastic resin, which causes double transcription (10a, 11a) of the sample marks (10, 11). For preventing the double transcription, groove areas (35, 36) are provided both sides of the sample mark area (32). The groove areas (35, 36) has an anchor effect at the time of injection molding.