A rolling bearing unit has an inner shaft and an inner race that is fitted on an outer circumferential surface of the inner shaft at one end side thereof. The inner race is fixed to the inner shaft by a clamping portion resulting from an end portion of the inner shaft. An annular stepped portion is formed on an outer end face of the inner race on a radially outward side thereof. A pulser ring is disposed within the stepped portion and is then held between the stepped portion and the clamping portion to thereby be fixed in place thereat.