The present invention provides a nonaqueous electrolytic solution capable of improving electrochemical characteristics at high temperatures, which comprises at least one organic phosphorus compound represented by the following general formula (I), an energy storage device using the nonaqueous electrolytic solution, and a specific organic phosphorus compound. (In the formula, R1 and R2 each independently represent an alkyl group, a cycloalkyl group, an alkenyl group, an alkynyl group, an alkoxy group, a cycloalkoxy group, an alkenyloxy group, an alkynyloxy group, a halogenoalkyl group, a halogenoalkoxy group, an aryl group, or an aryloxy group; R3 and R4 each independently represent a hydrogen atom, a halogen atom, or an alkyl group; m is an integer of from 1 to 4, n is 0 or 1, q is 1 or 2. When q is 1 and n is 0, X represents an alkoxy group, an alkynyloxy group, an alkyloxyalkoxy group, an aryloxy group, etc.; when q is 1 and n is 1, X represents an alkyl group, an alkynyl group, an alkoxy group, an alkynyloxy group, an alkyloxyalkoxy group, etc.; and when q is 2, X represents —O-L3-O—, —OC(═O)—C(═O)O—, or a single bond.)