An apparatus for reading subdivided information from an optical disk, which comprises a track groove and on which information is recorded along the track groove is disclosed. The apparatus includes an optical head, which irradiates the optical disk with light and generates an electric signal responsive to part of the light that has been reflected from the optical disk, read signal processing means for generating a wobble signal which has an amplitude changing with the wobble pattern from the electric signal, rise value acquiring means for sampling and holding an absolute gradient value of the wobble signal when the signal rises, fall value acquiring means for sampling and holding an absolute gradient value of the wobble signal when the signal falls, and subdivided information detecting means for determining the subdivided information by majority by comparing the values held by the rise and fall value acquiring means with each other.