Abstract: Provided is a method of preventing reverse current flow through an ion exchange membrane electrolyzer, which method is capable of preventing a reverse current from being generated after stopping operation of the ion exchange membrane electrolyzer. A method of preventing reverse current flow through an ion exchange membrane electrolyzer 100, the ion exchange membrane electrolyzer 100 having an anode chamber 107 housing an anode, a cathode chamber 110 housing a cathode, an anode solution-supplying manifold 121 to feed anode solution to the anode chamber 107, and a cathode solution-supplying manifold 124 to feed cathode solution to the cathode chamber 110.