An endoscope according to the present invention includes an elongated insertion section that is inserted into a subject, an attachment portion that is provided on the insertion section, and to which a circular cylindrical external appliance is attached, and a locking member that is disposed on a more distal end side of the insertion section than the attachment portion, and that prevents removal of the external appliance from the insertion section by abutting against a surface, of the external appliance, facing a distal end.
