An optical pickup is disposed which irradiates a laser beam onto an
optical disc where a guide groove having characteristics of thermal
interference (heat discoloration) is spirally formed. The optical pickup
irradiates the laser beam along the guide groove to conduct one of data
recording in which pits indicating a data length are formed, and
visible-image formation in which a part of the optical disc is
discolored. The laser beam irradiation position is controlled so that the
data recording is conducted with starting from the inner peripheral side
of the optical disc, and the visible-image formation is conducted with
starting from the outer peripheral side of the optical disc.