PURPOSE: To accomplish a small-sized frequency discriminating circuit enabling to perform a multi-information processing by a method wherein a selection delay time and a selection time are reduced by having the temporary memory and the high- speed reproduction of a frequency signal.

CONSTITUTION: The demodulation wave obtained through a band-pass filter, a detector 3 and a low-pass filter 4 is quantitized by a quantitizing circuit 15 and this signal wave fm is temporary memorized at a memory circuit 16. The control circuit 17 controls the memory circuit 16 so that the latter reads and memorizes the signal wave fm, and also controls the circuit 16 to reproduce the memorized contents at a high speed and the memorized contents are reproduced at a high speed which is N times faster than that when the signal wave was read in. And this high-speed reproduction wave Nfm is given to a odulator 7 which is subjected to time division checking by the output (fo+Nfn) by a programmable oscillator 13, a frequency fo ingredient is extracted through the intermediary of a selection filter 8 when the checking frequency is fn=fm and the discrimination of the frequency of the input signal can be done by performing a level inspection using a level detector 9.