An apparatus for electrolyzing sulfuric acid, the apparatus comprising an electrolytic cell comprising a cathode chamber having a cathode and an anode chamber having an anode, the cathode chamber and the anode chamber being separated by a diaphragm, a sulfuric acid tank configured to store the sulfuric acid, a supply pipe connecting the sulfuric acid tank to an inlet port of the anode chamber, a connection pipe connecting an outlet port of the cathode chamber to the inlet port of the anode chamber, a first supply pump provided on the supply pipe and configured to supply the sulfuric acid from the sulfuric acid tank to the cathode chamber through the supply pipe, and a drain pipe connected to an outlet port of the anode chamber and configured to supply to a solution tank a solution containing an oxidizing agent generated by electrolysis in the anode chamber.