PURPOSE: To reduce a noise of a reproducing beam obtained from a medium by superposing a high frequency current on a driving current of a recording semiconductor laser.

CONSTITUTION: The beam of the semiconductor laser 1 is faced to a magneto- optial recording medium 20 by a PBS 4 through a collimate lens 2 and a diffraction grating 3, and a prescribed track is irradiated by the beam through a lens 5. Magnetic field is applied from the rear side of the medium 20 by a magnetic head 6. The magnetic field is modulated by a modulation circuit 7 according to recording information, and magnetic recording is performed. A part of the laser beam is sent to an LD driver 10 through a detector 8 and an APC circuit 9. Further, a high frequency superposition signal is sent from a control circuit 11 to the LD driver 10, and a sample-and-hold control signal, etc., is outputted to the APC circuit 9. Thus, an LD 1 is output controlled and driven automatically, and further, the presribed high frequency current is superposed at a recording time, and the noise occurrence in the LD 1 due to a return beam from the medium is suppressed. Further, since the laser beam irradiates continuously at the recording time, the verify is the whole area.