Disclosed is a preamplifier circuit of a magnetic record regeneration apparatus with a write system and a read system, certainly verifying a write function in a short period of time. The preamplifier circuit includes, in the write system, a write driver; a current-voltage conversion circuit for converting the write current from the write driver into a corresponding voltage; a waveform shaping circuit for converting the output voltage from the current-voltage conversion circuit into a full-wave rectified waveform; a peak-hold circuit for holding a peak value of the output from the waveform shaping circuit; a filter circuit for outputting an average voltage of the output from the waveform shaping circuit; and a determination circuit for determining that the write driver is abnormal based on each output status of the peak-hold circuit and the filter circuit.