An intake manifold made of synthetic resin includes first, second and third members stacked in sequence and welded to form the intake manifold; a collector extending inside the intake manifold in a direction of a line of cylinders, a part of wall of the collector being formed by the third member; a plurality of branch passages formed substantially by the first and second members and wound around an outer periphery of the collector; and a connector passage leading from the collector to an outer peripheral side of the branch passage. The first, second and third members are respectively provided with first, second and third cylinder portions that are coaxially arranged with each other in a position between adjacent two branch passages. The connector passage is formed by the first, second and third cylinder portions with the connector passage communicating with an inside space of the collector.