A three-dimensional netted structure having an upper surface, a lower surface, two side surfaces a left end surface, and a right end surface, including at least a plurality of filaments helically and randomly entangled and thermally bonded together, wherein the filaments are formed out of a thermoplastic resin by extrusion molding followed by cooling with a liquid; and the netted structure is four-surface molded, the upper surface, the lower surface and the two side surfaces being molded. An apparatus and a method for manufacturing the three-dimensional netted structure.