A rolling bearing unit for a drive wheel comprises a hub and a double row rolling
bearing thereon. The hub has a first inner ring raceway formed on an inner ring
element integrally or separately formed with the hub in an intermediate portion,
and a fit cylindrical surface section in a part closer to the inner end of the
outer peripheral surface. A separate inner ring having a second inner ring raceway
is fitted on the hub, with the axially inner end surface pressed by a caulking
portion formed by plastically deforming a cylindrical section formed in the axially
inner end portion of the hub in a state that the inner ring is fitted on the fit
cylindrical surface section, to be fixed to the hub.
