To purify exhaust gas by a catalyst, to reduce a coating cost of the catalyst, and to reduce a production cost by carrying the exhaust emission control catalyst over the whole outer peripheral surface of spacer pipes arranged so as to cross an inside part of a muffler main body of a vessel shape.

The whole outer peripheral surface of plural spacer pipes 5 (1 to 3) is coated with an exhaust emission control catalyst 21. The whole inner peripheral surface of a tail pipe 7 and a part inserted into a muffler main body, are also coated with the catalyst 21. Exhaust gas agitated in the muffler main body is purified by contacting/reacting with the outer peripheral catalyst 21 of plural spacer pipes 5 (1 to 3). The exhaust gas contacts with the outer peripheral catalyst 21 of the tail pipe 7 in the muffler main body, and is purified by contacting/reacting with the inner peripheral catalyst 21 of the tail pipe 7 when passing through the tail pipe 7. The tail pipe 7 has an inserting length up to a central part of the muffler main body to pass the whole quantity of the exhaust gas, and can thereby efficiently purify the exhaust gas because of often contacting with the catalyst 21.