NOVELTY - The method involves arranging current collection unit (16) for positive electrodes so that projections face protrusions provided on intermediate conductive portion (24). A stacked core exposed portion (14) is provided between conductive portions. The sides of exposed portion is pressed by resistance welding electrodes (31) whose resistance welding face diameter is larger than diameter of projections provided on collector unit. Resistance welding is performed while projections contact the resistance welding faces of the resistance welding electrodes.    USE - Method for manufacturing square shaped secondary battery such as nickel-hydrogen secondary battery and lithium ion secondary battery used in electric vehicle, hybrid electric vehicle and motor vehicle.    ADVANTAGE - The weight of the secondary battery can be reduced. High capacity secondary battery can be obtained. The volumetric efficiency of the electrical storage apparatus can be improved. By providing protrusion in the convex portion and current collection portion of the intermediate electrically-conductive portion as projection, big nugget is formed in the core exposure portion arranged between the intermediate electrically-conductive portion and the current collection unit at the time of resistance welding. Hence welding strength can be increased. Since the contact condition between current collection unit and the resistance welding surface of the electrode for resistance welding is favorable when resistance welding is performed, the generation of sputter can be prevented. Since the sputtered dust stays at melted state on the surface of the current collection unit, reliable square secondary battery can be manufactured and malfunction of the square secondary battery can be prevented. Since the area of the electricity supply path in the state after pressurizing with the electrode for resistance welding can be reduced, the quality and efficiency of resistance welding can be improved.    DESCRIPTION OF DRAWING(S) - The drawing shows a side view of the secondary battery.    Stacked core exposed portion (14)    Current collection unit (16)    Insulation portion (20)    Intermediate conductive portion (24)    Resistance welding electrodes (31)