PURPOSE: To improve vertical resolution using a simple configuration by lowering a vertical scanning frequency of a video signal of the standard system and increasing number of horizontal scanning lines in a vertical period.

CONSTITUTION: An output video signal of an image pickup tube 12 is amplified 13 and led out to a video output terminal 16, and at the same time, led out to a gate circuit 17. A gate signal G1 is generated in the circuit 17 synchronizing with a synchronizing signal VD of a monitor 21 side and a synchronizing signal (1/N) VD of image pickup side, A video signal B is extracted and stored in a field memory 19. Renewal and rewriting of data in the memory 19 is made once during one field period of a modified video signal A. Accordingly, in the monitor 21 side, the video signal for one field in the memory 19 is synchronized to the standard system, and read and displayed repeatedly. By this way, the period devoid of video signal is interpolated and flicker is eliminated.