An information signal recording medium reproducing apparatus comprises an equalizer supplied with a frequency modulated composite video signal picked up from an information signal recording medium, a frequency demodulator for frequency-demodulating an output signal of the equalizer into a composite video signal, a synchronizing signal separating circuit for separating a horizontal synchronizing signal from the composite video signal, and a switching signal generating circuit for forming a switching signal from the horizontal synchronizing signal. The equalizer is supplied with the switching signal and has such a circuit construction that a frequency at which an output level versus frequency characteristic of the equalizer has a peak is reduced responsive to the switching signal during a predetermined time period in a vicinity of the front edge of the horizontal synchronizing signal to correct a distorted waveform of the frequency modulated composite signal caused by defects in the information signal recording medium.