An end faced on an outer side in a radial direction of a small diameter annular portion of a retainer is disposed on an inner side in a radial direction of a pitch conical face of a taper roller and an end face on an inner side in a radial direction of a large diameter annular portion is disposed on an outer side in the radial direction of the pitch conical face. Further, a portion of the small diameter annular portion opposed to a small diameter end face of the taper roller is disposed on the inner side in the radial direction of the pitch conical face and a portion of the large diameter annular portion opposed to a large diameter end face of the taper roller is disposed on the outer side in the radial direction of the pitch conical face.