PROBLEM TO BE SOLVED: To achieve an excellent observation by allowing the distal end surface of an insertion part in an endoscope to approach a wall surface in a diverticulum within an appropriate distance, even in a region such as a diverticulum of a colon.SOLUTION: When the operation ring 54 of a hood operation wire 52 is pulled, the wall surface for fixing the wire 52 in the body part 40 of an endoscope hood 3 is allowed to approach the distal end surface 30 of a distal end part 23. Consequently, the radial dimension of an edge part 42 in the body part 40 of the endoscope hood 3 is changed to be smaller than the outer diameter dimension of the distal end surface 30 of the distal end part 23, thereby facilitating burrowing into the inner part of the diverticulum 60 from the constriction 60a of the diverticulum 60 of a colon. On the contrary, when the hood operation wire 52 is pushed out, the wall surface for fixing the wire 52 in the body part 40 of the endoscope hood 3 is inclined outward from the axial core of the insertion part 11. Thus, the radial dimension of the edge part 42 in the body part 40 of the endoscope hood 3 is changed to be larger than the outer diameter dimension of the distal end surface 30 of the distal end part 23.
