To efficiently manufacture a strap with stable quality with compact, sanitary equipment by melting a solid lead alloy in a mold by high frequency induction heating or electric resistance heating.

A lead-acid battery strap is formed by immersing an electrode lug in a molten lead alloy in a mold and solidifying it. The molten lead alloy is prepared by melting the specified amount of solid lead alloy in the mold. Wire-like or powdery sold lead alloy is used. A coil for high frequency induction heating is placed in the lower part of the mold, the lead alloy is put into the mold, and lead alloy is melted by induction-heating the lead alloy for about 10 seconds. The electrode lug is immersed in the molten lead alloy, then the molten lead alloy is solidified to join the electrode lug and a strap. Or the mold is heated by directly passing electricity through the mold to melt the solid lead alloy. Since the amount of lead alloy of the strap is correctly controlled, the quality is stabilized.