A shaft portion of a joint outer ring where projections extending in an axial direction are provided is press-fitted into a hole portion of a hub wheel to thereby form recesses by the projections in an inner diameter surface of a shaft fitting hole of the hub wheel, by which a recess-projection fitting structure is constructed. An entire area of fitting sites of the projections and the recesses are brought into close contact. Moreover, a bolt member is fastened in a bolt hole provided in the shaft portion of the joint outer ring after the construction of the recess-projection fitting structure, which restricts separation between the hub wheel and the joint outer ring. As the bolt member, if an outer diameter of a seating surface thereof is d1 and a shaft diameter is d2, a bolt member satisfying a relational expression of 2.3≦(d1/d2)2≦4.9 is used.