Spin- and angle-resolved photoemission spectroscopy has been applied to the study of the surface and bulk electronic structures of a face-centered cubic (fcc) Co thin film. We have experimentally resolved a negatively spin-polarized surface resonance state of fcc Co/Cu(001) at 0.4 eV below the Fermi energy. Moreover, we have found that the surface resonance state exhibits a strong spin–orbit interaction through an investigation of magnetic dichroism in the angular distribution spectrum of Co/Cu(001).