Oxidation behavior of stainless steel surface was investigated at 450 degreesC in oxygen partial pressure of 1 x 10(-9) Torr using surface-sensitive photoemission spectroscopy (PES). At the initial stage of oxidation, a layer mixed with metallic chromium and oxygen existed on top of Cr2O3 layer, showing relatively high oxygen concentration compared to the Cr2O3 layer. The valence-band electronic structure of thr: oxide film was hardly affected by the presence of impurities such as Mn and Fe. Attenuation of chromium satellite peaks was observed when the oxide film contained metallic chromium. The authors propose that the attenuation might stem from the screening of charge excitations by free carriers from the metallic chromium.