A ligation treating apparatus including plurality of ligation rings aligned and held in a cylinder portion which is formed by an inner cylindrical portion and an outer cylindrical portion. A piston member for pushing out the ligation rings is provided in the cylindrical portion. Air introduction means for forcing air into the cylinder portion is also provided. An annular groove for holding the foremost ligation ring is formed at the front end of the inner cylindrical portion. An air discharge port is formed at the bottom of the annular groove. The air discharge port discharges air from the cylinder portion so as to stop the piston member when the ligation ring is moved out of the annular groove.