An endoscope system comprises plural video processor devices for an endoscope prepared for every video endoscope, a video signal switching device connected to each of the video processor devices for an endoscope, and a monitor connected to the video signal switching device. The video signal switching device comprises two video signal input terminals respectively connected to the video processor devices, a flip flop for generating an alternative switching signal in accordance with the rotational position of a switching dial, two switches of which one ends respectively connected to the video signal input terminals and which opens and closes in accordance with the switching signal generated from this flip flop, and a video signal output terminal connected to the other ends of these two switches.