Nitrided steel member and its manufacturing method

The present invention provides a nitrided steel member, which member is formed of iron nitride compound layer with a surface of a steel member of carbon steel for machine structural use steel or alloy steels composed of a mechanical structure, wherein, in IFe4N (111) / {IFe4N (111) + IFe3N (111)} intensity is represented is 0.5 or more, the above-described IFe4N (111) and IFe3N (111) are measured resulting for the surface of the nitrided steel member by X-ray diffraction X-ray diffraction peak intensity of (111) crystal plane of Fe4N and X-ray diffraction peak intensity of (111) crystal plane Fe3N; the thickness of the iron nitride compound layer is 2μm ~ 17μm.