PURPOSE: To improve productivity by continuously executing the processes that freezed material of lead alloy is processed and deformed under the hot processing and is then cooled, thereafter it is formed as an expanded sheet, it is then sent to the heat treatment, it is filled with active substance and finally it is punched to the specified shape.

CONSTITUTION: The fused fluid 1 of Pb-Ca-Sn system alloy is supplied between the rolls 3, 3'. A strip 4 in the thickness of about 2.1mm obtained is sent to a heating furnace 5 and is then heated. It is then hot-rolled by the cold rolls 7, 7' and simultaneously cooled. Thereby, a thin plate strip 9 in the thickness of 0.85mm can be obtained. It is then sent in succession to the expanders 10, 10' to form the expanded metal sheet 11. This metal sheet is then subjected to the heat treatment in the heating furnace 12 and is then sent to the active substance filling apparatus 14. Thereby, is is filled with the active substance. Thus, it is punched into the specifid shape by the punching apparatus 19 in order to obtain the electrode plate. Therefore, productivity can be improved remarkably and mechanical strength of electrode plate can also be enhanced by continuously executing such processings.