A lithium ion secondary battery at least includes a positive electrode (10), a negative electrode (20), and an electrolyte solution. The positive electrode (10) at least includes a positive electrodeactive material and a binder. The positive electrode active material includes 0.08 mass% or above of lithium carbonate with the balance being a lithium complex oxide. The binder is at least one selected from a group consisting of polytetrafluoroethylene, polyethylene oxide, and carboxymethylcellulose. The electrolyte solution at least includes a solvent and a lithium salt. The solvent is at leastone of N,N-dimethylformamide and dimethylacetamide. A concentration of the lithium salt in the electrolyte solution is 1.9 mol/l or above and 2.3 mol/l or below.