PURPOSE: To prevent the malfunction of a synchronous processing circuit when a feeble electric field and a ghost signal are generated and to improve picture quality.

CONSTITUTION: A time constant variable filter circuit part 20 is connected to the AFC terminal P5 of an AFC detection circuit 32. The time constant variable filter circuit part 20 consists of a first filter circuit 21 which is fixedly connected to the AFC terminal P5, a second filter circuit 22 where connection on/off with the AFC terminal P5 is switched through a switch circuit 23 and a switch control circuit 24 controlling the opening/closing of the switch circuit 23. The switch control circuit 24 connects only the first filter circuit 21 to the AFC terminal P5 in a synchronized pull-in period immediately after power is supplied or when a channel is switched, connects the two filter circuits 21 and 22 to the AFC terminal P5 in parallel so as to improve filter effect in the other period. Thus, the responsiveness of an AFC operation when the feeble electric field and the ghost signal are generated is forced to be dull, and a synchronous processing is stabilized.