Abstract: An electrode active material mainly includes an organic compound having, in a structural unit thereof, a conjugated diamine structure represented by the general formula (I), and an electrolyte includes a carbonate ester compound represented by the general formula (II). In the formulae, R1 to R4 represent substituted or unsubstituted alkyl groups, or the like, whereas X1 to X4 represent a hydrogen atom or a substituent. A secondary battery is achieved which has a high energy density and thus produces a high output, and has favorable cycle characteristics with a small capacity degradation even in the case of repeating charge and discharge.