An endoscope system includes: an endoscope including an elongated insertion portion provided with a bendable bending portion, the insertion portion being inserted into a duodenum and a first balloon to a fourth balloon for moving a one-side surface of a distal end portion located nearer to a distal end side than the bending portion in the insertion portion in parallel with respect to a field of view direction S of an objective lens which is a diameter direction of the insertion portion, separately from bending of the bending portion, the one-side surface being located in a circumferential direction along an insertion direction W of the insertion portion and parallel to a central axis P of the insertion portion.
