A gear having a high fatigue strength can be produced relatively inexpensively. The gear is produced by plastic working using a steel material containing C.ltoreq.0.01 wt %, Si.ltoreq.1 wt %, 0.05 wt %.ltoreq.Mn.ltoreq.0.5 wt %, P.ltoreq.0.1 wt %, S.ltoreq.0.03 wt %, 0.02 wt %.ltoreq.sol.Al.ltoreq.0.1 wt %, 0.8 wt %.ltoreq.Cu.ltoreq.1.7 wt %, and 0.02 wt %.ltoreq.Ti.ltoreq.0.1 wt %, the balance being Fe and inevitable elements. The gear is subjected to soft nitriding, serving as artificial aging, after a solution treatment. The resulting gear has a sufficiently deep, surface hardened layer. Further, the gear may be produced inexpensively since the simultaneous performance of the artificial aging and soft nitriding saves energy.