An endoscope includes an insertion section including an insertion main body extended along a longitudinal axis and being inserted into a lumen, an operation section provided to a proximal direction side of the insertion section, and an attachment unit including a fin portion spirally extended along the longitudinal axis and provided to an outer peripheral direction side of the insertion section to be rotatable about the longitudinal axis with respect to the insertion main body. The endoscope includes a rotary gear rotating about a gear axis to rotate the attachment unit about the longitudinal axis, and a built-in extended member extended through an inside of the insertion main body and an inside of the operation section from a distal end portion of the insertion section along the longitudinal axis. The insertion main body includes a partition member separating the built-in extended member from the rotary gear.
