PURPOSE: To surely detect a pulse corresponding to a code signal inserting position in video signals reproduced from, for example, a video disk, by using a counter circuit which counts clocks of a prescribed times of a horizontal frequency.

CONSTITUTION: Composite synchronizing signals are inputted from a terminal 21 and differentiated waveforms are formed by a differentiation circuit 24. A reference generator 23 generates a clock signal having (n) pieces of clocks in one horizontal scanning period. A counter circuit 22 counts the clock signal from the generator 23 and receives the signal of the circuit 24 at its clear terminal CL. A logical circuit 25 inputs 1/2n-1- and 1/2n-divided outputs out of each divided outputs of the circuit 22 and leads out the AND of the inputs. A gate circuit 26 inputs the AND and composite synchronizing signals and gates the composite synchronizing signals and detects only a specified synchronizing pulse during the period when the AND is at a prescribed level only.