To reduce the contact resistance between the positive and negative electrodes of a dipole late provided with the positive and negative carbon felt electrodes in a redox flow battery.

Multiple sheets of carbon felt cut with the carbon felt having the direction of fibers in the plane direction into a tape shape are laminated, an insulating or conductive resin in filled 2 in the carbon felt except for both faces where the cut faces of the carbon felt of a laminated product 1 are exposed and their vicinities to form a plate as a whole, and electric resistance is reduced, or a sheet of carbon felt is folded in zigzag with a strip shape used as a unit, the insulating or conductive resin is filled in the carbon felt except for both side faces of the long sides of each strip exposed on the surface by folding and their vicinities to form a plate as a whole, and electric resistance is reduced.