Recently, as a replacement for conventional laparotomy surgeries, endoscopic surgeries such as a laparoscopic surgery are performed. An endoscopic surgery is performed by making a small incision in the body surface and inserting therein a minimally-invasive insertion device such as a rigid endoscope, forceps and an incision tool of narrow diameters, and its effect is comparable to that of a laparotomy surgery. In endoscopic surgeries, the incisions can be made relatively smaller than those in laparotomy surgeries, thus reducing physical and mental burden of the patient.
On the other hand, as conventional insertion devices, there is a flexible endoscope that has a configuration in which the tip of the insertion section can be bent (for example, see Patent Literature 1 or 2 and Non-Patent Literature 1) and a rigid endoscope having a rigid, rod-like insertion section. Also, there is a multifunctional endoscope comprising one endoscope equipped with a plurality of means including an observation means such as a CCD camera and a treatment means such as grip forceps or a snare (for example, see Non-Patent Literature 2 or 3).