To improve the life property of a secondary battery.

This secondary battery has one or a plurality of positive electrode plates 101 each having a lithium-contained compound oxide as an active material, one or a plurality of negative electrode plates 103 each having a carbon system material that stores and releases a lithium ion as an active material, and an electrolytic solution that intermediates the transportation of an ion accompanying electrochemical reactions of the positive electrode plate 101 and the negative electrode plate 103. The ionic conductance of a separator 102a arranged inside the secondary battery 10 is made lower than that of a separator 102b arranged outside the secondary battery 10.