A method for refining a metal such that, after a base material derived from the metal is melted by being irradiated with an electron beam, the base material is refined by solidifying the base material which was melted, the method including: a step melting all of the base material by irradiating the electron beam over an entire surface of the base material loaded inside a water-cooled crucible placed inside a high vacuum atmosphere; a step gradually solidifying the base material which was melted from a molten metal bottom part of the base material which was melted toward a molten metal surface part at a side being irradiated by the electron beam by gradually weakening an output of the electron beam while maintaining a condition in which the base material which was melted is irradiated with the electron beam; and a step removing a molten metal part which is not solidified, after the base material which was melted is solidified to a certain percentage.