The purpose of this study was to investigate the correlation between corrosion resistance and surface composition of an experimental Cr casting alloy in a saline solution containing fluoride. The alloy had a greater resistance to corrosion in a fluoride-containing saline solution than did commercially pure titanium. However, with confirmed dissolution of titanium and chromium, it meant that the fluoride in the saline solution corroded the alloy slightly.X-ray photoelectron spectroscopy analysis revealed that the surface composition of the alloy consisted of titanium and chromium oxides containing hydroxide.Theratio in the surface oxide film decreased when immersed in fluoride-containing saline solution, that is, the surface oxide film became chromium-rich oxide. Therefore, the alloy obtained good corrosion resistance to fluoride due to formation of a chromium-rich oxide film.