This endoscope treatment system is provided with: an endoscope device that comprises a cylindrical member that is capable of bending operation and a bending operation section that bends the cylindrical member； and an endoscopic treatment tool that is inserted in a treatment tool channel of the endoscope device. The endoscopic treatment tool is provided with an insertion section that can be inserted into the body and an operation section that is arranged on the proximal end of the insertion section. The insertion section comprises a sheath having an outer diameter that makes insertion in the treatment tool channel possible and a knife wire that is arranged on the tip section of the sheath and that is for cutting living tissue. A lumen is formed in the sheath and has an inner diameter that makes it possible to insert a guide wire therein, and said sheath comprises an outlet that opens at the distal end part of the sheath and that communicates with the lumen and an inlet that opens at the outer peripheral surface of the proximal end part of the sheath. The operation section comprises: a port that communicates with the inlet and that has formed therein a through hole in which it is possible to insert the guide wire； and a locking section that is capable of locking to the endoscope device so that the opening direction of the through hole of the port faces the bending operation section side when the insertion section is inserted in the treatment tool channel.L'invention concerne un système de traitement d'endoscope qui comprend : un dispositif d'endoscope qui comprend un élément cylindrique qui peut réaliser une opération de courbure, et une section d'opération de courbure qui courbe l'élément cylindrique ； et un outil de traitement endoscopique qui est inséré dans un canal d'outil de traitement du dispositif d'endoscope. L'outil de traitement endoscopique comprend une section d'insertion qui peut être insérée dans le corps, et une section de fonctionnement qui est dispos
