PURPOSE: To provide a muffler that has a high noise elimination effect by combining two external shells and an internal plate that are stamp formed from metal plate in the nested relationship, and forming a tube array between groove formed in the internal plate and the other external shells.

CONSTITUTION: A muffler is composed of a metal stamp formed first external shell 12 and a second external shell 12, 16 and an internal plate 14. The first external shell 12 has an outskirts flange 18 and a projective nonplanar portion 20, inlet and outlet flanges 22, 24 are formed in two opposing sides of the flange 18. The internal plate 14 has an outskirts flange 28 and a nonplanar portion 30, inlet and outlet flanges 32, 34 that form the outlet and inlet in corporation with the flanges 22, 24 are formed in the flange 28. And, a snake shaped groove 36 connected to the outlet and inlet is formed in the nonplanar portion 30, and plural holes 48, 50, 52 opened at the space between the internal plate 14 and the second external shell 16 are formed in the groove 36.