A high-definition optical disk and a high-definition optical disk drive, which record data on lands and grooves. Wobbles are formed in grooves and lands of an optical disk, and address information is embedded in the wobbles. The wobbles are formed so as to become in phase with each other in the grooves. An address of the land sandwiched between the grooves is detected from the wobble of the groove. When the wobble of the land is not an in-phase wobble but is of opposite phase, a gray code of the wobble is substituted with a binary address such that 0 is achieved when the gray code is converted into the binary address. As a result, even in the case of the wobble of opposite phase, the address information about the land is made coincident with address information about an inner-radius-side adjacent groove, thereby determining address information about the land.