1. A video image storage device, comprising: an image signal input means converting image signals in input video signals having various types of scanning lines into digital image signals by analog-to-digital conversion; a frame memory means memorizing the converted image signals; a signal output means outputting the memorized image signals in the form of digital signals when required; an input timing signal generating means which generates sampling clock signals synchronized with horizontal synchronizing pulses of the input video signals; an output timing signal generating means which causes the frame memory means to output the memorized image signals; and a frame memory control means which controls signal memory function of the image signals from the signal input means to the frame memory means in accordance with signals from the input timing signal generating means and controls signal output function of the image signals from the frame memory means to the signal output means in accordance with signals from the output timing signal generating means.