Abstract: A muffler having a tubular cylindrical fiber-reinforced resin body with tapered extremities ending in short necks, through said body being disposed an axial aluminum tube with extremities projecting outwardly from the assembly, said tube being perforated in the section inside the body and the internal space between the body and tube being filled with sound-absorbing material. During assembly of the muffler, the internal tube and the external body are fastened by means of clamps, with the interposition of gaskets adhered with the body resin itself in order to avoid leakage between the tube and body. The sound absorbing material is also mounted on pre-fabricated channels in the body, thus eliminating the need of handling it.