To obtain a diol in a good yield by hydrogenating a dicarboxylic acid in the presence of a ruthenium-rhenium-activated carbon carrier catalyst in mild conditions at a high reaction rate.

This method for producing the diol comprises hydrogenating a dicarboxylic acid preferably represented by the formula: HOOC-R-COOH [R is a divalent (substituted) 0-30C hydrocarbon group] in the presence of a ruthenium-rhenium-activated carbon carrier catalyst (in an amount of 0.005-25 mole ruthenium metal % based on the dicarboxylic acid) preferably in an ether solvent (isopropyl ether or dimethoxyethane) at 50-230°C. The activated carbon used in the catalyst is preferably produced by a steam-activation method using wood as a raw material, and has a specific surface area of 1100-1400 m2/g. The catalyst is obtained by carrying the rhenium component on a ruthenium- activated carbon carrier catalyst.