the object of the present invention is to realize reduction of the level jitter generated from a noise component at a signal saturation level or a waveform distortion in a portion except for signal polarity portions , and good error characteristics . in the present invention , a predetermined upper or lower limit value is set to reproduction signals , the reproduction signals are subjected to a limiter processing for correcting reproduction signals of the upper limit value or more , or the lower limit value or less to the level of the upper limit value or the lower limit value , respectively , the signal subjected to the limiter processing is subjected to a partial response equalizing processing , and pr reproduction is performed to improve the level jitter at pr detection time and the error rate at information reproduction time .