PROBLEM TO BE SOLVED: To provide an elastic stopper having superior holding of sealing performance such as without liquid leakage in time of needle puncture, or with excellent holding force or resilience to needle coming-off, and to provide a medical cap including the same and a method for producing the medical cap.SOLUTION: This medical cap 10 includes: the elastic stopper 11 and an outer frame body 12 including an upper frame part 12a holding a peripheral part of the elastic stopper 11 from a needle puncture face 14 side by the inner wall thereof, and a lower frame part 12b holding it from a liquid contact face 15 side by the inner wall thereof. The lower frame part 12b is formed with at least one caulking part 18 for caulking the elastic stopper 11, and the elastic stopper 11 is formed with at least one cavity part 13 for integrally molding the caulking part 18 together with the outer frame body 12, in an optional position in a second peripheral part 19 of the liquid contact face 15. The elastic stopper 11 is not welded in a contact face with the upper frame part 12a, is welded in a contact face with the lower frame part 12b, and furthermore is welded in a contact face with the caulking part 18 in the cavity part 13, too.
