A recess-projection fitting structure includes projections extending in an axial direction on an outer diameter surface of a shaft section of an outer joint member or an inner diameter surface of a hole of a hub wheel, press-fitting the projections in another of the outer diameter surface and the inner diameter surface along the axial direction, and forming recesses brought into contact and fitted with the projections by press fitting in the other of the outer diameter surface and the inner diameter surface, the projections and the recesses being held in contact with each other through intermediation. An outer member is fitted in a hole of a knuckle of a vehicle. Annular grooves are formed respectively in an outer peripheral surface of the outer member and an inner peripheral surface of the hole of the knuckle, and a snap ring is engaged with both the annular grooves.