Magneto-optical disk device and medium

PURPOSE:To eliminate fluctuation of a playback signal in its edge position due to thermal interference between pits by forming a test pattern on an optical disk and controlling a constituting element of an optical pulse train based on a comparison result with a test signal. CONSTITUTION:The optical disk 1 is irradiated with a light beam by a light source 8, and an information signal to be recorded is converted into a code train by a coder 4. The light beam of the light source 8 is modulated to be the optical pulse train in accordance with the code train, and the optical disk 1 is irradiated with this optical pulse train to be recorded as a recording mark. Reflected light from the optical disk 1 is received by a detector 9 from an optical head and is formed into an electric signal waveform, and the electric signal processed in waveform by a waveform equalizer 11 is pulsified by a shaper 13. The code train is detected by a discriminator 15 from the pulse signal, and this code train is restored to the information signal by a decoder 17. The test pattern is formed by a trial writer 3, and this result is reproduced and compared by a comparison discriminator 16, and then from the comprision result, the optical pulse train is controlled at least on either of its power level, width and space.