The invention provides an endoscope system for the early detection of suture failure. Parts of the large intestine separated by the resection of a tumor are sutured by using a suturing member 167. A sutured portion is imaged. An oxygen saturation image 180 is generated by imaging the oxygen saturation of the sutured portion based on image information obtained by the imaging. The generated oxygen saturation image 180 is displayed on a display device 14. In the case of suture failure, a low oxygen region 180a is displayed in the oxygen saturation image.
