An active material for a secondary battery has excellent large current charge-discharge characteristic and a high energy density. The secondary battery is composed mainly of the active material having a conductive polymer compound represented by formula B or F as the positive electrode. Because this conductive polymer compound works as an active material and has conductivity per se, the use of a conductivity enhancer can be omitted, and the energy density is high. An improvement in the capacity of a secondary battery using the active material above or a decrease in the internal resistance can be realized.