PURPOSE: To avoid occurrence of the flicker noise caused by dropout of the video signal as well as to prevent the S/N deterioration dut to the crosstalk by securing the coincidence between the writing and reading synchronous pulses to the memory device.

CONSTITUTION: When writing order signal (c) of control part 7 receiving synchronous pulse (b) is supplied to winding part 8a, relay circuit 8 switches relay contact 8b to make side M to lead writing video signal (a) directly to video monitor 5 from TV camera 2. In this case, picture memory 4 carries out the regular writing of the video signals equivalent to one cycle based on pulse (b). When the 1-cycle writig is over, signal (c) disappears with contact 8b switched to the break side. And video signal (e) read out of memory 4 based on pulse (b) is supplied to monitor 5.