An endoscope (2) includes an image sensor (21) that is disposed at a front end portion (10) of an insertion portion (6) of the endoscope (2)； a circuit board (24) that is mounted with the image sensor (21)； a plurality of electric wires (27) that are electrically connected to the circuit board (24)； and a retention member (28) that has a retention portion (33) tying up the electric wires (27)； and the retention portion (33) is disposed in a narrowed section that is provided in the insertion portion (6) and inside a part adjacent to the front end portion in an axial direction of the insertion portion (6) and narrowed in a narrowing direction perpendicular to the axial direction so that the electric wires (27) are tied up to be longer in a direction perpendicular to the narrowing direction and the axial direction than in the narrowing direction.
