We investigate the enhancement of the magneto-optical (MO) effect via the evanescent wave in MO structures composed of GdFe thin layers and two dielectrics. The MO Kerr rotation and the figure of merit (FOM) among the Kretschmann, Otto and direct-irradiation configurations are compared. The data obtained by experiment and calculation both show that the standing evanescent wave in the metal layer realized in the former two configurations enhances the MO Kerr rotation and FOM. Furthermore, the Kretschmann configuration appears to be superior to the Otto configuration in terms of the efficiency of MO Kerr enhancement.