An endoscope system of the present invention has an endoscope which acquires a direct-view field of view image and a side-view field of view image of an object to be observed, a light source apparatus which supplies an illuminating light for illuminating the object to be observed, a detection section which acquires a predetermined detection result based on a predetermined output signal or predetermined output information, which occurs due to an operation of the endoscope, an image processing unit which generates and outputs a video signal including the direct-view field of view image and the side-view field of view image in a same screen, and a light adjustment area selection section which detects a brightness of the direct-view field of view image and a brightness of the side-view field of view image individually, selects one of field of view images of the direct-view field of view image and the side-view field of view image as a light adjustment target based on the predetermined detection result, and performs control of the light source apparatus so that the one of the field of view images reaches a predetermined brightness target value suitable for observation.
