A playback signal is supplied to a delay amplifier and a noise comparator. The delayed playback signal is supplied to a comparator, which compares the delayed playback signal with the playback signal and provides a first comparison signal to a pulse adjustment circuit. The noise comparator compares the playback signal with threshold signals and provides a second comparison signal to the pulse adjustment circuit. The pulse adjustment circuit generates the peak detection signal at each point when the signal level of the first comparison is inverted, and determines the peak detection signal to be invalid when the signal level of the playback signal falls within the range between the threshold signals. A read signal is generated based on the valid peak detection signal.