An endoscope insertion portion (1) of the present invention is an endoscope insertion portion provided with a distal-end rigid portion (1a) having at least an illumination portion (4) and an observation portion (5), a bending tube portion (1b) coupled to the distal-end rigid portion (1a) and to which a plurality of bending rings (10) are coupled by a pivot attachment portion (11), and a flexible tube portion (1c) coupled to the bending tube portion (1b) and a main body operation portion (2), in which the bending ring (10) is provided with an insertion path through which an operation wire (20) for bending the bending tube portion (1b) by a remote control from the main body operation portion (2) is inserted, and an inward projection portion (31) is provided in the front and rear position in the axial direction of the insertion path.
