PURPOSE: To offer a method for manufacturing a hardening treated steel having excellent dimensional accuracy.

CONSTITUTION: This manufacturing method is constituted of a primary hardening stage of hardening the steel to be treated, a tempering stage of subjecting the above steel to be treated to tempering at ≥450°C to the austenitization temp. or below, a working stage of subjecting the above steel to be treated to working, a secondary hardening stage of improving the strength of the above steel to be treated and a tempering stage of subjecting the above steel to be treated to final refining. By the tempering stage of executing tempering at ≥450°C to the austenitization temp., softening caused by the tempering occurs to facilitate its working as well as it shrinks to the dimention upon the end of the final tempering stage. Successively, by the working stage of subjecting the steel to be treated to working, working excellent in accuracy is executed without anticipating dimensional change in accordance with the hardening and tempering, by which the hardening treated steel having high accuracy can be manufactured.