Method for surface treating a die made of metal in which a low energy, pulsed electron beam, which does not scatter, performs a treatment over a wide area due to presence of anode plasma in a chamber in which the electron beam is formed to smooth and gloss a surface of the die and increase a surface hardness and corrosion resistance of the die. The irradiation may be performed with an energy density not less than 1 J/cm² per pulse, at least 5 pulse irradiations and a pulse duration of at least 1 s. A die subjected to the surface treatment method exhibits improved surface smoothness and glossiness, as well as high corrosion resistance.