An insertion assisting tool (60) is provided and includes an insertion path (70) in which the insertion portion of an endoscope is inserted and a tube for fluid (72,74) which is formed along the axial direction at the tubular wall portion of the insertion path. The insertion path has a circular shape in its section orthogonal to the axial direction. The tube is configured in a manner that the sectional shape thereof along the axial direction is longer in the circumferential direction than the radial direction.
