An optical disk and a method for identifying the optical disk making it possible to identify a recording system of the optical disk easily in a short time by a recording and reproduction apparatus when a groove-recording system and a land-recording system are both employed in one kind of optical disk, such as, for example, a BD-R. Specifically, a polarity upon reproducing wobble information is made to be the same in both an optical disk of groove-recording system and the optical disk of a land-recording system. The recording system of the optical disk that shows the same wobble polarity irrespective of the recording system can be easily detected by finding a tracking polarity that can recognize the wobble information by changing the tracking polarity, whereby the start-up time of the recording and reproduction apparatus can be shortened.