PURPOSE: To prevent the degradation in low-temp. process intensity and to prevent the destruction of recorded data by providing the outer peripheral part of a recording medium with regions for recording information of high rewriting frequencies.

CONSTITUTION: An optical modulation overwriting magneto-optical disk D having a diameter of 130mm is initialized over the entire surface and is then set in an magneto-optical device equipped with a semiconductor laser for recording and reproducing of a wavelength 780nm. This disk D is rotated at 3000rpm and signals of 4MHz are recorded in parts of a radius 55 to 60m and radius 30 to 35mm. At this time, the laser beam intensity pH attains 14.0mW in the outer peripheral part and 10.0mw in the inner peripheral part. In such a case, the time from the rise to fall of the laser beam intensity and the time from the fall to the rise are equal. The signals recorded at the reproducing beam intensity of 1.0mW are thereafter reproduced. If C/N is measured, the result thereof attains 56dB on both inner and outer peripheries.