Abstract: A bending piece of a bending portion for endoscope is provided with: an annular wall portion; a plurality of wire inserting portions in which the wall portion has a first wall thickness; thin wall portions having a second wall thickness thinner than the first wall thickness; and a thick wall portion that is a part of the wall portion different from the thin wall portions between the plurality of wire inserting portions around a longitudinal axis, the thick wall portion formed to have a third wall thickness that is equal to or less than the first wall thickness and is thicker than the second wall thickness.

Abstract: A bending portion includes: a bending piece group including a plurality of first bending pieces; and a second bending piece including coupling protruding portions for coupling to a coupling frame so as to resist torsion about the longitudinal axis, and including, on a proximal end side, third contact surfaces facing a direction of the longitudinal axis, the second bending piece including inside a second insertion portion for allowing insertion of internal components, the second insertion portion being formed so as to be coincident with the first insertion portion provided in each of the first bending pieces on a same projection plane, the second bending piece being interposed between the coupling frame and the bending piece group such that the third contact surfaces and a distal-most position of the bending piece group are in rotatably contact with each other.

Abstract: A bending portion includes: a bending piece group including a plurality of first bending pieces; and a second bending piece including coupling protruding portions for coupling to a coupling frame so as to resist torsion about the longitudinal axis, and including, on a proximal end side, third contact surfaces facing a direction of the longitudinal axis, the second bending piece including inside a second insertion portion for allowing insertion of internal components, the second insertion portion being formed so as to be coincident with the first insertion portion provided in each of the first bending pieces on a same projection plane, the second bending piece being interposed between the coupling frame and the bending piece group such that the third contact surfaces and a distal-most position of the bending piece group are in rotatably contact with each other.

Abstract: A bending piece of a bending portion for endoscope is provided with: an annular wall portion; a plurality of wire inserting portions in which the wall portion has a first wall thickness; thin wall portions having a second wall thickness thinner than the first wall thickness; and a thick wall portion that is a part of the wall portion different from the thin wall portions between the plurality of wire inserting portions around a longitudinal axis, the thick wall portion formed to have a third wall thickness that is equal to or less than the first wall thickness and is thicker than the second wall thickness.