An exhaust muffler comprising an outer cylindrical body, front and rear end plates mounted on each end of the outer cylindrical body, porous plates fitted on the insides of the outer cylindrical body and each of the end plates, and partition plates for dividing the internal space of the outer cylindrical body into several chambers, wherein when joining the component parts with each other, three or four component parts are superposed via their joint portions each on the other and integrally joined by laser beam welding so as to obtain a reduction of welding steps and minimize the thermal influence in the manufacturing process while ensuring an air-tight condition of the partitioned chambers. When an exhaust pipe and tail pipe are connected to the end plates, respectively, they are laser beam welded to the end plates in a superposed fashion. Alternatively, the outer cylindrical body is formed in a multiple-layered construction with inner and outer panels which are so formed integral with each other as to squeeze or press inwardly, when assembling, an internally installed unit over its fill periphery, thereby not requiring particular measures for fixedly securing the internally installed unit to the outer cylindrical body. Preferably the outer cylindrical body and end plates are formed on an aluminum-plated or a stainless steel plate, thereby dispensing with a coating after welding.