The purpose of the present embodiment is to provide a lithium secondary battery having high energy density due to containing a positive electrode active material that operates at a voltage of at least 4.5 V with respect to lithium, and having excellent cycle characteristics. The present embodiment is a lithium secondary battery having a positive electrode containing the positive electrode active material, and an electrolyte containing a nonaqueous electrolyte solvent, said lithium secondary battery characterized in that the positive electrode active material operates at a voltage of at least 4.5 V with respect to lithium, and the nonaqueous electrolyte solvent contains a fluorine-containing phosphoric acid ester represented by a prescribed formula.