In an endoscope 10 according to the invention, an opening 62 for supplying or suctioning a fluid to or from the inside of a balloon 60 is provided on the surface of an insertion portion 12. A shutter member 66 is provided in the opening 62, and a shutter member 66 is attached to the insertion portion 12 so as to be movable between a closed position where the opening 62 is closed and an open position where the opening 62 is opened to the outside.