PURPOSE: To enable a stable discharge performance to be securely obtained by mechanically abrading or roughing the surface of a negative active material touching a negative terminal before the negative active material is pressed upon and affixed to the negative terminal.

CONSTITUTION: A lancet 34 made of metal or hard plastic is moved in the direction indicated by the arrow so as to abrade or roughen the surface of a negative active material 18 made of lithium by means of the pointed end of the lancet 34. As a result, a thin oxidized film covering the surface is either scraped off or scratched causing a large part of unoxidized foundation to be exposed. Next, before the foundation is oxidized, the surface is brought into contact with the inner surface of a negative terminal 12 before mechanical load is applied so as to affix the surface to the negative terminal 12, thereby achieving a metallurgical binding and realizing an electrically stable good contact condition.