A first balloon is fitted to an insertion portion of an endoscope and a second balloon is fitted to an insertion aid member. An end connector of a tube is connected to a balloon control device that supplies and sucks air into and from the first balloon and the second balloon. A duct that communicates with the first balloon, a duct that communicates with the second balloon, and a duct that communicates with a clearance between the insertion portion and the insertion aid member are formed in the end connector.