PURPOSE: To obtain a good quality regenerative signal by using a laser beam for heating a medium with such power as larger than regenerative laser beam power but smaller than laser beam power by which a pit is formed.

CONSTITUTION: A laser beam pulse for forming the pit, a regenerative laser beam and the laser beam for heating medium with the power as larger than the regenerative laser beam power but smaller than the laser beam by which the pit is formed are applied to this method. Consequently, the recording medium is irradiated by the laser beam which does not form the pit prior to an irradiating time of a recording laser beam, and hence the irradiating time of the recording laser beam as of the laser beam pulse for recording after raising the temperature of the medium not to exceed its write-enable temperature limit can be shortened, thus obtaining the good quality regenerative signal with less peak shift.