A method for producing furan-2,5-dicarboxylic acid (FDCA) is provided which can efficiently and quantitatively producing FDCA under mild conditions, without employing an expensive catalyst and with a reduced energy consumption. A furan ring compound having two functional groups selected from a hydroxymethyl group, a formyl group and a carboxyl group in the 2- and 5-positions of the furan ring, is oxidized with a metal permanganate in an alkaline environment to produce furan-2,5-dicarboxylic acid. Advantageously, the alkaline environment contains at least one of alkali metal hydroxides and alkali earth metal hydroxides, and the oxidation is performed at a temperature of from 1 to 50° C. by adding the permanganate metal salt to the alkaline aqueous solution containing the furan ring compound.