An endoscope system includes: a first processor configured to process a first imaging signal acquired by a first endoscope; a second processor communicably connected to the first processor and configured to process second imaging signal acquired by a second endoscope; a mode switch configured to switch a processing mode of image processing; an image processor configured to execute first image processing on the first imaging signal when the mode switch switches the processing mode to a first processing mode and to execute second image processing on an signal input from the second processor when the mode switch switches the processing mode to a second processing mode; and a video-signal output unit configured to generate a video signal for display based on an output signal from the image processor and output the video signal to an external device.