PURPOSE: To allow the utilization of the impressed magnetic field at the time of the max. by executing irradiation with light pulses before the intensity of the impressed magnetic field maximizes.

CONSTITUTION: A magnetic field impressing device 2 is driven at a specified frequency (f) and a magnetic field is impressed to a magneto-optical recording medium 1. The on and off of the laser light of an optical head 3 are controlled via a driving means 5 controlled by the reference clock of the timing precedent to the timing when the impressed magnetic field outputted by a reference clock generating means 4 attains the max. value in accordance with the phase signal of the impressed magnetic field. A head 3 is irradiated with the laser pulses of ≤fX1/2 width in precedence to the timing when the magnetic field is maximized in this way and the impressed magnetic field is maximized at the time when the temp. at which the recording is executed passes the temp. at which the magnetization direction is frozen in the cooling process after the head is heated. As a result, the magnetic field at the time of the max. is utilized and the recording with the small jitter and decreased bit errors is executed at a high speed.