PROBLEM TO BE SOLVED: To provide an optical adapter attachment/detachment aid for an endoscope and an endoscope system capable of easily discriminating the type of an optical adapter attached to a tip part of an insertion part of an endoscope and reducing the diameter of the insertion part by minimizing the optical adapter and the tip part.SOLUTION: An optical adapter attachment/detachment aid 7 for an endoscope includes: an aid body 15 which holds an optical adapter 20 to be attached and detached to/from a tip part 11 of an insertion part 10 belonging to an endoscope 4 of an endoscope device 2 and is freely attached and detached to/from an aid attachment part 42 provided at a place other than the insertion part 10 in the endoscope device 2 and an identification part 21 provided at the tip part 15a of the aid to have information on a type of the optical adapter 20, identified by a reading part 41 provided in the aid attachment part 42.
