PURPOSE: To prevent malfunction and to enlarge the range of discriminatable TV systems by generating the discrimination pulse signals of a prescribed pulse width in synchronism with horizontal synchronizing signals and discriminating first/second fields based on the level state of the discrimination pulse signals at a leading edge part in vertical synchronizing signals.

CONSTITUTION: The discrimination pulse signal generation circuit 35 of a field discrimination circuit 1 generates the discrimination pulse signals Si provided with the pulses of a prescribed width raised at the leading edge of horizontal synchronizing pulses. A discrimination output circuit FF37 inputs the signals Si and the vertical synchronizing signals Sv, fetches the level state of the signals Si at the leading edge part in the signals Sv and outputs first discrimination signals Sf at the time of a high level and second discrimination signals Ss at the time of a low level respectively. Thus, the malfunction hardly occurs even when the jump-in of noise or the like occurs and even systems other than a normal NTSC system can be discriminated.