Bearing unit for wheel and manufacturing method thereof

A bearing unit for a wheel has a rotary ring (16) whose raceway surface is hardened by a thermal process. In this bearing unit, the side surface of a fitting flange (13) for fixedly joining a rotary body for braking and a wheel, is formed by working in a predetermined configuration after the raceway surface of the rotary ring has been subjected to the thermal process. The raceway surface of the rotary ring is worked in a predetermined configuration and dimensions on the basis of the side surface of said fitting flange. This bearing unit can restrain disagreeable noises and vibration from being caused upon braking.