Auxiliary insertion and removal tool and endoscope

An auxiliary insertion and removal device that is inserted into or removed from a lumen in a state where an inserting section of an endoscope having a longitudinal axis is inserted into and that aids insertion and removal of the inserting section into or from the lumen, the auxiliary insertion and removal device comprising:

• a tubular main body section that allows the inserting section to be inserted therein and is rotatable around the longitudinal axis;
• a fin section that is arranged on an outer peripheral surface of the main body section and spirally arranged in a desired direction to be wound around the longitudinal axis;
• a spiral tube section that is arranged on the main body section and arranged to be wound around the longitudinal axis in the same direction as the fin section or a direction opposite to the fin section;
• and
• a diameter change preventing section that prevents a diameter of the spiral tube section from expanding when the spiral tube section is wound in the same direction as the fin section, or prevents the diameter of the spiral tube section from contracting when the spiral tube section is wound in the direction opposite to the fin section.