A first side-face spline of a hub spindle and a second side-face spline of a constant velocity joint each has a tooth tip formed by tip tilted surfaces tilted from tooth flanks constituting a tooth chevron, an internal angle of the tooth tip is set to be less than 180 degrees, and a tooth tip-side perpendicular distance, which is a perpendicular distance between a tooth tip virtual intersection and a first virtual plane is set larger than a bottom land-side perpendicular distance, which is a perpendicular distance between a bottom land virtual intersection and a second virtual plane.