An electrode plate unit capable of suppressing the internal short circuit caused by flashing that is formed on the end portion of a positive electrode plate and a battery using the same. The electrode plate unit includes a group of electrode plates in which a plurality of positive electrode plates and a plurality of negative electrode plates are laminated alternately via separators, a positive electrode collector plate connected to one side face of the group of electrode plates for connection to the positive electrode plate, and a negative electrode collector plate connected to another side face of the group of electrode plates for connection to the negative electrode plate, wherein the edge portion of the positive electrode plate is protruded from the edge portion of the negative electrode plate on the entire side face excluding the side face to which the negative electrode collector plate of the group of electrode plates is connected.