PROBLEM TO BE SOLVED: To provide a method for reusing indirect heating steam, which can reduce the steam consumption rate of a pickling facility.SOLUTION: The method for reusing indirect heating steam is used in the pickling facility, which includes a pickling tank for pickling a steal sheet and a water washing tank for washing an acid solution stuck to the pickled steel sheet in this order. The method for reusing indirect heating steam comprises the steps of: supplying steam into a tube disposed on the inside of the pickling tank to heat the acid solution in the pickling tank or supplying the steam into another tube disposed on the outside of the pickling tank and withdrawing the acid solution from the pickling tank, bringing the withdrawn solution into contact with the outside of the tube to heat the acid solution and returning the heated acid solution to the pickling tank; recovering the used steam used for heating the acid solution; and supplying the recovered steam to the water washing tank so that the s
