A first mold has a recessed surface portion. A second mold that has a protruding surface portion and a flat surface portion is laid on top of the first mold, thereby forming a first cavity between the recessed surface portion and the protruding surface portion and a second cavity between the first mold and the flat surface portion. The first cavity and the second cavity are filled with a first resin material. A third mold having a flat inner wall surface is laid on top of the first mold and the first resin, thereby forming a space between the inner wall surface and the first resin so as to correspond to the protruding surface portion. This space is filled with a second resin material, and thus an acoustic coupling member is molded.