A muffler including an inlet member, an outlet member, an exhaust-gas cleaning device including an exhaust-gas cleaning material, the exhaust-gas cleaning device including a first inlet side coupling section and a first outlet side coupling section detachably coupled to the inlet member and the outlet member by couplers, and an intermediate member including a second inlet side coupling section and a second outlet side coupling section detachably coupled to the inlet member and the outlet member by couplers same as the couplers, instead of the exhaust-gas cleaning device. The intermediate member is a cylinder body allowing exhaust gas in the inlet member to flow directly to the outlet member without passing through the exhaust gas cleaning material, and includes a resistance generation section providing the intermediate member with exhaust resistance substantially equal to that of the exhaust-gas cleaning device.