an inner ring is fitted on one - end side of an inner shaft and fixed to the inner shaft by caulking . during the caulking , the inner shaft is supported by a caulking receiving jig . a receiving section to which the jig is in contact is provided at a position near the one - end side of the inner shaft , for example , at a position nearer to the inner ring than a raceway section formed on the outer periphery on the other side of the inner shaft . as a result , a caulking load acting from a caulking jig on the inner shaft plastically deforms only a desired portion .