An endoscope system includes an insertion portion, an observation window provided in the insertion portion and configured to acquire a forward visual field image, an observation window provided in the insertion portion and configured to acquire a lateral visual field image, and an image processing portion. The image processing portion detects a set detection target in the lateral visual field image, generates an image signal of the forward visual field image and an image signal of the lateral visual field image, and in the case that the detection target is detected, outputs the image signal of the forward visual field image and the image signal of the lateral visual field image.
