A non-aqueous electrolytic solution includes a phosphoric acid diester salt, which can suppress deterioration of charge-discharge characteristics of a power storage element, and can suppress the rise in internal resistance after storage at high temperature. The phosphoric acid diester salt is represented by the following chemical formula (1): in which Mn+ represents a hydrogen ion, an alkali metal ion, an alkali earth metal ion, an aluminum ion, a transition metal ion, or an onium ion, R1 and R2 are different from each other and represent a hydrocarbon group having 1 to 10 carbon atoms, or a hydrocarbon group having 1 to 10 carbon atoms and having at least one of a halogen atom, a heteroatom, and an unsaturated bond, and n represents a valence.