Wheel hub rolling bearing unit for a motor vehicle with a cold forged inner ring and a seal

A wheel hub rolling bearing unit for a motor vehicle is provided with an inner ring member (10) having multiple flange portions (18). The inner ring member (10) is formed by cold forging and has a tapered surface (35) formed thereon in a state of a forged surface. The tapered surface (35) gradually increases in diameter from an inner side toward an outer side in a vehicle lateral direction over a region from a position near root portions of inner side faces of the flange portions (18) in the vehicle lateral direction to a position radially outward of an outer periphery of an outer end portion of an outer ring member (51) in the vehicle lateral direction. A seal member (60) is attached to the outer periphery of the outer end portion of the outer ring member (51). At a distal end portion of the seal member (60) a seal lip (64) is formed which is in sliding contact with the tapered surface (35) in the state of a forged surface.