A bearing apparatus for a driving wheel of vehicle for rotatably supporting the driving wheel relative to a body of a vehicle has a wheel hub, integrally formed with a wheel mounting flange, a constant velocity universal joint and a double row rolling bearing assembled as a unit. A separate inner ring is press fitted onto a cylindrical portion of the wheel hub. An outer joint member of the constant velocity universal joint is fitted within the wheel hub. The bore surface of the wheel hub is formed with a hardened irregular portion. The wheel hub and the outer joint member are integrally connected with making the hardened irregular portion of the wheel hub bite into the outer circumferential surface at a fitting portion of the outer joint member by radially outwardly expanding the fitting portion of the outer joint member. The hardness of the bore surface of the fitting portion of the outer joint member is higher than that of the core portion of the fitting portion of the outer joint member.