Abstract: A storage battery or a secondary battery is capable of improving the utilization of an active material and obtaining a high energy density, using raw materials having costs substantially equal to those of a conventional lead storage battery especially as a negative-electrode plate of the secondary battery. The negative-electrode active material for the secondary battery is a kneaded mixture including: a raw active material having a metal and an oxide of the metal; and carbon in such an amount that the total absorption number thereof is at least 4.7 ml per mol of the raw active material, in which the kneaded mixture contains no sulfates or sulfates in an amount of 7×10?2 mol or smaller per mol of the raw active material. The negative-electrode active material has a specific volume of 2.2×10?1 to 5×10?1 ml/g with subjected to no formation. The carbon is acetylene black or furnace carbon.