PURPOSE: To eliminate the need for accurate adjustment and to obtain a discriminating circuit with stable operation, by multiplying a burst signal with a continuous wave having a frequency closer to any of two burst signal frequencies and shifting the burst frequency to a low frequency band.

CONSTITUTION: A burst signal is separated from a chroma signal inputted from the 1st input terminal 1 with a burst gate pulse inputted from the 2nd input terminal 2 at a burst gate circuit 4 and the burst signal is multiplied with a continuous wave of a single frequency inputted from the 3rd input terminal 11 at a multiplication circuit 9. In selecting the frequency of the continuous wave to a chrominance subcarrier frequency of a PAL system television signal, the output of the multiplication circuit 9 is almost a DC for the PAL signal and a signal for the SECAM signal, in which the R-Y signal component is 30kHz and the B-Y signal component is 180kHz. As a result, the SECAM signal can easily be discriminated via a frequency selecting circuit 10, a detecting circuit 7 and a rectifying circuit 8.