Method for Operating Redox Flow Battery

Provided is a redox flow battery operating method which comprises a step for mixing, at a prescribed cycle, a prescribed volume of a positive electrode electrolytic solution and a negative electrode electrolytic solution, wherein the prescribed cycle is defined as x hours selected from within a range of not more than 320 hours, and the prescribed volume is set such that, when the storage volume set for one of a positive electrode tank and a negative electrode tank is defined as y%, y is not less than a value represented by y=0.01%×x, however, y is not more than a value represented by y=0.9%×x if x is selected from within the range of not more than 30 hours, and y is not more than 27.0% if x is selected from within the range of more than 30 hours but not more than 320 hours.