An endoscope insertion aid configured so that an endoscope can be quickly inserted to a site to be treated from an incision in the surface of a body cavity to reduce a burden to the patient. An endoscope insertion aid (1) is provided with an over tube (20) which is inserted into a body cavity (vagina), an inner tube (30) which is inserted into the inside of the over tube, a holder unit (40), and an air leakage prevention unit (50). The inner tube (30) has high rigidity, and when the inner tube is inserted into the over tube (20) which is curved, the curved shape of the over tube is deformed into a rectilinear shape. When pushing and inserting a tip section (32) at the tip of the inner tube (30) from an incision provided in the surface of the body cavity, the operator can easily exerts a force on the tip section.
