EXHAUST MANIFOLD WITH CATALYST

PROBLEM TO BE SOLVED: To prevent lowering of an engine output due to interference between exhaust gases, to effect efficient purification of exhaust gas, and besides to provide a compact exhaust manifold with a catalyst. SOLUTION: An exhaust manifold 1 with a catalyst comprises a flange 2 on the exhaust port side, branch pipes 3a-3d, and primary collection pipes 4a and 4b, and a secondary collection pipe 5. A secondary collection pipe 5 comprises a first pipe 11 having a first partition plate 11a; a monolith catalyst converter 20, and a second pipe 12 having a second partition plate 12a and a flange 12b on the coupling side. A monolith catalyst 22 has a number of gas passages 23, and each of the gas flow passages 23 is extended along the axial direction of the secondary collecting pipe 5. Thereby, when exhaust gas flowing through a flow passage S1a → a flow passage S1b flows through the monolith catalyst 22, the exhaust gas hardly interferes with exhaust gas flowing through a flow passage S2a →a flow passage S2b.