CrN_x film was deposited on S45C by cathodic arc ion plating process. The deposition of CrN_x layer was carried out at the various N₂ partial pressure of 8×10^(-4) torr to 2×10^(-2) torr under the bias voltage of -200V. All the coated specimens were analyzed by XRD and SEM for structural characterization and the wear and corrosion behavior was compared with that of hard Cr coated specimens by ball-on-disc wear test and electrochemical polarization measurement. The CrN_x coatings at all deposition conditions appeared to be very dense and fine granular structure. The CrN_x coating deposited at 1×10^(-2) torr showed the highest CrN(220) intensity and a maximum hardness of Hk 2700 which is twice of that of the hard Cr coating. The wear resistance of CrN_x coated S45C against AISI 52100 steel balls was highly improved compared to that of the hard Cr coating. The CrN_x coatings also enhanced the resistance of pitting and crevice corrosion. This improvement was associated with the formation of the CrN_x coatings with dense and fine granular structures without microcrack which exists in all the electroplated hard Cr coating.