A highly reliable optical disk apparatus adapted to record and reproduce the information in and from plural types of optical disks is disclosed. An acquisition unit acquires a predetermined signal from the reflected light obtained by radiating a predetermined laser on each of the optical disks. A comparator compares the waveform of the signal acquired by the acquisition unit with the comparative waveform of the signal stored in a memory beforehand and obtained from the radiated laser corresponding to the optical disk. An identification unit identifies the type of the optical disk based on the result of comparison by the comparator.