Bearing device and this method of preparation

A bearing device comprising a shaft body having an axially cylindrical portion in a free end side thereof and a rolling bearing fitted around an outer peripheral surface of the shaft body, wherein the cylindrical portion is bent and deformed radially outward by a rolling caulking to be caulked thereby on an outer end face of an inner ring of the rolling bearing. An inner peripheral surface of the cylindrical portion is formed by a turning work, and a residual stress left in a surface layer of the inner peripheral surface of the cylindrical portion by the turning work is set to a value capable of restraining a crack generation ratio in the inner peripheral surface to less than a predetermined rate, desirably to not more than 5 kgf/mm .