The invention relates to a two-part disinfectant composition for hard articles, which comprises a first preparation and a second preparation, wherein the first preparation comprises a powder mixture (A) comprising an alkali metal salt (A-1), a water-soluble copper salt (A-2), a compound (A-3) represented by general formula (1) and a nonionic surfactant (A-4) represented by general formula (2) wherein the alkali metal salt (A-1) has such a characteristic property that an aqueous solution thereof is basic and the ratio of the amount of the component (A-3) to the amount of the component (A-2) is 3.0 to 20 by mole, and wherein the second preparation comprises an aqueous hydrogen peroxide solution (B-1); and a one-part disinfectant composition for hard articles, which comprises a powder mixture comprising the components (A-1) to (A-4) mentioned above and an inorganic peroxide (B-2) capable of releasing hydrogen peroxide in water, wherein the ratio of the amount of the component (A-3) to the amount of the component (A-2) is 3.0 to 20 by mole. The disinfectant compositions for hard articles have a high disinfection effect on the surfaces of hard articles, can exhibit good hydrogen peroxide stability in water, and have low foamability. Also disclosed is a method for disinfecting the surface of a hard article using the disinfectant composition for hard articles.