X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) using synchrotron radiation were applied for the clarification of the surface oxidation behavior of chromium nitride films which were prepared by cathode arc ion plating method. The XPS analysis of the oxidized samples demonstrated that the presence of nitrogen-containing intermediates generated N1s XPS peaks at higher binding energies than that for nitrogen in chromium nitride. In the N K-edge XAS spectra of the oxidized samples, a sharp peak assigned to 1s-π^* transition was observed at a higher energy than that for the N2p-Cr3d peak assigned to chromium nitride. The above results indicate that, with replacement of the nitrogen in chromium nitride by oxygen, the released nitrogen occupies the interstitial position in the chromium oxide matrix as molecular or atomic nitrogen. A part of the interstitial nitrogen in the chromium oxide matrix is evolved from the surface with further progress of oxidation. Oxynitride species, described as CrNxOy, are not likely formed during the course of the surface oxidation.