An inexpensive ring spring having high strength and a method for producing the same, are provided. The ring spring can be obtained, for example, by raw material preparation, bending formation, welding, and disk formation performed in this order. The ring spring is formed to have no edge by welding two edge parts of the raw material, and has a welded metal part that is formed at the interface of the two edge parts of the raw material, and a welded heat-affected zone that is formed around the welded metal part and heated by welding, and exhibits tensile strength of 1000 MPa or more. Since the ring spring has sufficient tensile strength as a disk spring and a wave spring, quenching and tempering are not necessary. Furthermore, since the product can be prevented from being deformed due to quenching and tempering, dimensional accuracy of the product can be improved.