PURPOSE: To reduce the interference of noise in a video signal period and to track a target with high accuracy by putting generated noise of a switching power source in blanking periods of the horizontal synchronizing signal of an image pickup device.

CONSTITUTION: A synchronizing circuit 18 receives the horizontal synchronizing signal from the image pickup device and actuates a driving circuit 12 to turn on and off a transistor TR11 while actuating an exciting energy absorbing circuit 20 through a gate circuit 19. At this time, when the charging voltage of a capacitor C15 exceeds a specific value, the circuit 20 is actuated through the circuit 19. Then the TR22 in the circuit 20 is turned on to supply a current from a DC power source 21 through the winding n3 of a transformer 17 and at the same time, the charged energy of the transformer 17 is regenerated on an input side. Then an absorbing circuit 20 operates in blanking periods of the horizontal synchronizing signal to regenerate the energy remaining in the transformer 17 on the power source input side. Consequently, the current of the winding n3 becomes zero in the blanking periods of the horizontal synchronizing signal and the generation of noise is put in the blanking periods.