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.