This exhaust manifold (12) includes: an outer casing (18) includes: an outer shell (22); a flange (24) which is welded to the outer shell (22) and which has a surface (24B) for abutment against an engine cylinder head and at least one aperture (28) which opens at the abutment surface (24A), at least one inner channel (20) which is arranged in the outer casing (18) and which opens via an aperture (28). The or each inner channel (20) is formed from a ceramic material; and extends from one side to the other of the flange (24) through the or each aperture (28) and comprises a continuation (32) outside the outer casing (18) which extends outwards beyond the abutment surface (24A).