In the present invention, a high-purity metallic tin suitable for use in an EUV exposure device is provided through use of an oxidation-resistant metallic tin, the oxidation-resistant metallic tin containing 99.995 mass % or more of tin, and unavoidable impurities, and the thickness of an oxide film being 2.0 nm or less when the surface of a cut face of the oxidation-resistant metallic tin is measured by AES.