A cell frame in which the structure of a positive electrode electrolyte flow path and the structure of a negative electrode electrolyte flow path are different from each other, a cell stack in which the structure of at least one of the positive electrode electrolyte flow path and the negative electrode electrolyte flow path differs between the cell frame positioned at the center and the cell frame positioned at an end, the cell stack being configured such that electrical resistance in at least one of the positive electrode electrolyte flow path and the negative electrode electrolyte flow path increases from the cell frame positioned at the center toward the cell frame positioned at the end, and a redox flow battery utilizing them.