The present invention is to provide a bound stopper, which has high mechanical strength, is excellent in durability against fatigue breaking, settling or the like when a heavy load is repeatedly received, and is easy to be produced, in which the bound stopper comprises a polyurethane foam obtained from a polyurethane foam composition containing an isocyanate component and a blowing agent, and the isocyanate component contains a urethane prepolymer having an isocyanate group, the urethane prepolymer being obtained from a polyol component, a polyrotaxane containing a cyclic molecule having an active hydrogen group as a constituent, and an isocyanate.