PURPOSE: To eliminate a chrominance signal invaded in a luminance signal by providing a polarity conversion circuit which decides a phase of an output of a selection circuit depending on an output of a decision circuit, a phase of a 1st sum signal and a phase of a 1st difference signal and a subtractor which subtracts an output of the polarity conversion circuit from the 1st sum signal to the separator.

CONSTITUTION: When an input sg6 to a polarity conversion circuit 23 is '1', the circuit 23 outputs a signal with a same polarity as that of an input sg3 and a signal outputted from a selection circuit 22. On the other hand, when the input sg6 to a polarity conversion circuit 23 is '0' and an input sg7 to the polarity conversion circuit 23 is '1' (when an output of a subtractor 17 is negative), the circuit 23 outputs a signal with a same polarity as that of the input sg3 and the signal outputted from the selection circuit 22. A subtractor 11 subtracts an output of a multiplier 24 from a signal Yh1 and outputs a signal as a high frequency component Yh2 of a final luminance signal. The signal Yh2 is given to a subtractor 13, in which the signal Yh2 is subtracted from a high frequency component of the luminance signal S11 and a chrominance signal is obtained and outputted from an output terminal 15. Moreover, the high frequency component Yh2 of the luminance signal is added to a low frequency component of the luminance signal outputted from an LPF 2 at an adder 12, the luminance signal is obtained and outputted from an output terminal 14.