An endoscopic incision system includes: an endoscope; a cylindrical member for covering at least a distal end of an insertion section of the endoscope; and at least an incision section for incising a living tissue, the incision section being provided to a distal end of the cylindrical member and being capable of being exposed from the distal end of the cylindrical member outwardly. In this configuration, the radially expanding incision section will not be twisted or bent, and the incision section prevented from inadvertent fall-off can maintain the desirable shape when it is operated and rotated.