A nonaqueous electrolytic solution which comprises: a nonaqueous solvent, LiPF 6; and a fluorosulfonic acid salt represented by formula; M(FSO 3) X wherein M is a metal atom, N 4, or P 4 where R is either an organic group having 1-12 carbon atoms or a hydrogen atom, wherein not all of the four R's are hydrogen atoms, the R's may be the same or different, and a part or all of the four R's may form a ring in cooperation with the nitrogen atom or phosphorus atom to which the R's have been bonded; when M is a metal atom, x indicates the valence of the metal atom M and is an integer of 1 or larger; and when M is N 4 or P 4, x is 1, wherein the ratio of the molar content of FSO 3 in the nonaqueous electrolytic solution to the molar content of PF 6 in the nonaqueous electrolytic solution is 0.001-1.2, and wherein the nonaqueous electrolytic solution satisfies (i) the following condition 2, or (ii) the following conditions 1 and 2: Condition 1: the nonaqueous electrolytic solution further comprises at least one selected from the group consisting of a cyclic carbonate having a fluorine atom, a cyclic carbonate having a carbon-carbon unsaturated bond, a cyclic sulphonic acid ester compound, a compound having a cyano group, a diisocyanate compound, fluorophosphoric acid lithium salts other than LiPF 6, lithium imide salts, and a lithium salt having an oxalate group, Condition 2: the solvent contains at least one selected from the group consisting of saturated cyclic carbonates, chain carbonates, cyclic carboxylic acid esters and chain carboxylic acid esters. M is a metal atom, N 4, or P 4 where R is either an organic group having 1-12 carbon atoms or a hydrogen atom, wherein not all of the four R's are hydrogen atoms, the R's may be the same or different, and a part or all of the four R's may form a ring in cooperation with the nitrogen atom or phosphorus atom to which the R's have been bonded; when M is a metal atom, x indicates the valence of the metal atom M and is an integer of 1 or larger; and when M is N 4 or P 4, x is 1, wherein the ratio of the molar content of FSO 3 in the nonaqueous electrolytic solution to the molar content of PF 6 in the nonaqueous electrolytic solution is 0.001-1.2, and wherein the nonaqueous electrolytic solution satisfies (i) the following condition 2, or (ii) the following conditions 1 and 2: Condition 1: the nonaqueous electrolytic solution further comprises at least one selected from the group consisting of a cyclic carbonate having a fluorine atom, a cyclic carbonate having a carbon-carbon unsaturated bond, a cyclic sulphonic acid ester compound, a compound having a cyano group, a diisocyanate compound, fluorophosphoric acid lithium salts other than LiPF 6, lithium imide salts, and a lithium salt having an oxalate group, Condition 2: the solvent contains at least one selected from the group consisting of saturated cyclic carbonates, chain carbonates, cyclic carboxylic acid esters and chain carboxylic acid esters. Condition 1: the nonaqueous electrolytic solution further comprises at least one selected from the group consisting of a cyclic carbonate having a fluorine atom, a cyclic carbonate having a carbon-carbon unsaturated bond, a cyclic sulphonic acid ester compound, a compound having a cyano group, a diisocyanate compound, fluorophosphoric acid lithium salts other than LiPF 6, lithium imide salts, and a lithium salt having an oxalate group, Condition 2: the solvent contains at least one selected from the group consisting of saturated cyclic carbonates, chain carbonates, cyclic carboxylic acid esters and chain carboxylic acid esters.