An endoscope includes an insertion section including an insertion main body extended along a longitudinal axis, 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, and an operation section provided to a proximal direction side of the insertion section. The insertion main body includes an active bending portion bending by a bending operation in the bending operation input section, a passive bending portion provided to the proximal direction side of the active bending portion and passively bending when external force acts thereon, at least a part of the attachment unit being placed to the outer peripheral direction side of the passive bending portion, and a flexible portion provided to the proximal direction side of the passive bending portion and being less flexible than the passive bending portion.
