Abstract: A stepped insulating ring having a large-diameter upper portion, a small-diameter foot portion, and a step portion formed on the inside is inserted from a top opening of a bottomed cylindrical can containing a plate group and electrolyte and the small-diameter foot portion is set onto the plate group,a peripheral portion of a cover in which a safety valve is incorporated is set onto the step portion of the stepped insulating ring, and the areas to be sealed where an inside wall of top opening of the bottomed cylindrical can faces an outside wall of the large-diameter upper portion of the stepped insulating ring and an inside wall of the large-diameter upper portion faces a peripheral portion of the cover is formed, andwhen crimping operation on said areas to be sealed is performed from the outside of the upper part of the bottomed cylindrical can to form a closed construction,a sealing compound consisting of oily bitumen, organic solvent, and paraffin base oil is applied to the areas where an inside wall of t