Catalytic converter apparatus for engine

A catalytic converter apparatus for reducing pollutants from an engine having a plurality of cylinders, comprising an upper casing for mounting on the engine and having branch pipes extending to the engine and through which exhaust gas discharged from the respective cylinders in said engine is led, a lower casing connected to said upper casing for forming an exhaust manifold in cooperation with said upperr casing, said lower casing having a discharge port for said exhaust gas, a catalyst casing disposed within said exhaust manifold and having a support member extending therefrom and held between abutting surfaces of said upper and lower casing, said catalyst casing having a hollow substantially cylindrical inner core with a perforated cylindrical wall and an open upper end and a closed lower end, and an outer core having a perforated cylindrical wall and disposed coaxially with said inner core to define a space therebetween and having upper and lower end portions closing both the upper and lower ends of said space, and a catalyst layer in said space, said support member having an inner peripheral portion fixedly secured to the upper end of said outer core and an outer peripheral portion of the shape of a flat annular flange extending between the abutting surfaces between said upper and lower casings, and bolts inserted through said casings from above said upper casing for coupling said upper and lower casings to each other and clamping said support member therebetween.