Angle-resolved X-ray photoelectron spectroscopy (AR-XPS) has been used for studying the surface segregation of chromium in a copper-0.4 mass% chromium alloy. The influence of the chromium segregation on native oxide layers formed on the surface in this alloy has also been studied. According to a simple layered model assuming thin homogeneous layers, the average surface concentration chromium was found to increase up to about 15 at% on the alloy surface by annealing up to about 1000 K under ultra high vacuum. The AR-XPS results for the alloy surface with chromium segregation, which was exposed to air, showed that the growth of the native oxide layer of copper was not significantly suppressed by segregated chromium. This small influence of chromium segregation on the native oxide layer is considered to result from the relatively high oxidation rate of copper and the microscopic heterogeneity of chromium segregation on the alloy surface.