PURPOSE: To record and reproduce under a optimum recording condition and reproducing conditions by obtaining respectively optimum values from the results obtd. by changing phase differences, deflection directions and the recording power of a light source by respective adjusting elements and reproducing and recording trial writing information and using these values and storing them.

CONSTITUTION: A magneto-optical recording medium 7 previously on which the trial writing information (Td) is recorded, is irradiated with a laser beam of the light source 5 via a beam splitter 6 and a polarization direction rotating element 2. The phase difference element 1 changes the phase difference of the reflected light entering from the medium 7 via the element 2 and the splitter 6 and then, the element 2 changes the polarization direction by driving of respective motors 3, 4 to reproduce, Td. The optimum phase difference and polarization direction to maximize the amplitude of the respective reproduced signals are determined. Further, Td is recorded on the medium 7 by changing the recording power of the light source 5 at a specified interval and thereafter, the optimum recording power is determined from the reproduced error rate. As a result, the respectively determined optimum values are used by storing these values in the specific region of the medium 7. The information is thus recorded and reproduced under the respectively optimum conditions.