Even when a cell electrode plate with broader width is press formed to enhance bulk density of electrode active material, it is made possible to positively and reliably provide a high-quality cell electrode plate with good productivity. From upstream to downstream in a travel direction of a cell electrode plate including a core member with electrode active material applied thereon, an uncoiler, a tension applicator, a four-high mill type roll press device, a thickness detector, a tension applicator and a coiler are arranged in the order named.