To prevent the degradation in jointing strength in the vicinity of engine mounting flanges in relation to a vehicular intake manifold provided with a plurality of branch pipes horizontally arranged side by side whose projection chart to a vertical plane has a shape bent nearly at 90° and whose one-side ends are commonly connected to a surge tank, and the engine mounting flanges commonly continuously mounted to the other-side ends of the respective branch pipes, and particularly in relation to a vehicular intake manifold composed by welding a pair of jointing members formed of a synthetic resin to each other.

A welding margin along the pressing direction 39 of a part corresponding to a slanting part 32a out of welding margins set before welding in at least one of first and second jointing members 15 and 16 along a jointing line 32 is set larger than that along the pressing direction 39 of the remaining parts other than the slanting part 32a of the jointing line 32.