The objective of the present invention is to provide a highly reliable lead storage battery capable of demonstrating sufficient cycle life characteristics even when used under relatively intense idling stop control conditions. This lead storage battery contains a positive electrode plate comprising a positive electrode grid and a positive electrode active substance, a negative electrode plate comprising a negative electrode grid and a negative electrode active substance, a pole plate group comprising the positive electrode plate and the negative electrode plate layered through a separator therebetween, a battery container having a plurality of cell chambers, each housing the pole plate group and an electrolytic solution, and a lid for sealing the opening of the battery container. The ratio P/N, which is the mass P of the positive electrode active substance over the mass N of the negative electrode active substance, is between 1.25 and 1.65 inclusive, and the negative electrode grid contains bismuth in the amount of between 1 ppm and 300 ppm inclusive.