There is disclosed a lead storage battery comprising a group of plates housed in a battery jar, and an electrolyte injected therein to impregnate the group of plates with the electrolyte, thus performing formation treatment, the lead storage battery being adapted to be used in a partial state of charge where the state of charge is confined within the range of more than 70% to less than 100%, wherein the group of plates are formed of a stack constituted by a large number of negative substrates comprising grid substrates filled with a negative active material, by a large number of positive substrates comprising grid substrates filled with a positive active material, and by a porous separator interposed between the negative electrodes and positive electrodes, and the electrolyte contains at least one kind of ion selected from the group consisting of aluminum ions, selenium ions and titanium ions.