The present invention provides a secondary battery which is less expensive, whose safety is extremely high, which is of large capacity as well as good cyclic characteristic, and which uses an aqueous solution for the electrolytic solution. A lithium secondary battery according to the present invention is constituted by including a positive electrode, formed by binding a positive-electrode raw-material mixture including a positive electrode active material, a negative electrode, formed by binding a negative-electrode raw-material mixture including a negative electrode active material, and an electrolytic solution, comprising an aqueous solution in which a lithium salt is dissolved, said positive electrode active material including at least one of a layered structure lithium-manganese composite oxide whose basic composition is LiMnO.sub.2 and an olivine structure lithium-iron composite phosphorus oxide whose basic composition is LiFePO.sub.4. The present lithium secondary battery can be used in the fields of communication appliances and information-related appliances, and as an electric source for electric automobiles and the like.