PURPOSE: To prevent the deterioration in the picture quality by subtracting an arithmetic signal obtained by operating a lower side band component of an FM signal or an arithmetic signal obtained by operating the lower side band component and the carrier frequency component of the FM signal from the demodulation signal after FM demodulation thereby cancelling the undesired component generated at demodulation.

CONSTITUTION: A 1st low side band f1 passes through a low pass filter LPF 6 and doubled by a doubler circuit 7. Then the double component 2f1 passes through an LPF 8 to obtain an output of an arithmetic circuit 3. The moire component fm after the demodulation by the n-th order side band is expressed as fm=2fc-nfs=nf1-(n-2)fc, where fc is the carrier frequency of the FM signal, fs is the signal frequency and f1 is the 1st side band frequency. Then the nf1-(n-2)fc component is formed at the arithmetic circuit 3 from the carrier frequency fc and the 1st side band frequency f1 and the said moire component fm is subtracted from the demodulation signal demodulated by the pulse count type demodulator 2 from the FM signal coming from the input terminal 1 at the subtractor 4 and the result is outputted from an output terminal 5.