A rocking-chair nonaqueous secondary battery, which uses an ion other than monatomic ions as a charge carrier, and in which the ion moves in and out of both the positive electrode and the negative electrode, can be provided by using a nonaqueous secondary battery electrolyte comprising a salt containing a charge carrier comprising a molecular ion. The nonaqueous secondary battery further comprises a positive electrode containing a positive electrode active material, and a negative electrode containing a negative electrode active material, wherein the positive electrode active material and the negative electrode active material are both materials that allow doping and dedoping of molecular anions (e.g., conductive polymers, organic radical polymers, polymers having a ferrocene skeleton, conductive carbon materials, or organic sulfur compounds), or the positive electrode active material and the negative electrode active material are both materials that allow doping and dedoping of molecular cations (e.g., inorganic active materials, redox active molecules having a carbonyl group, redox active molecules having an imine skeleton, or redox active molecules containing a sulfur atom).