PURPOSE: To provide the synchronizing separation circuit capable of obtaining a more stable synchronizing signal without being affected by external disturbance such as noise or dropout.

CONSTITUTION: An asynchronous clamp circuit 1 clamps an input video signal and a pulse is obtained by slicing the signal at a 1st synchronizing separation circuit 2. When the pulse width of the pulse is within a prescribed range, a synchronization detection circuit 3 discriminates it as a synchronizing signal and a clamp pulse generating circuit 4 generates a clamp pulse based on an edge of a synchronizing signal. Then a synchronization clamp circuit 5 is worked by the clamp pulse to obtain a video signal of a stable blanking level. Synchronizing separation is performed from the video signal by a 2nd synchronizing separation circuit 6.