A nonaqueous electrolytic solution of an electrolyte salt dissolved in a non-aqueous solvent, which comprises at least one organic phosphorus compound represented by the following general formula: wherein R 1 and R 2 each independently represent an alkyl group having from 1 to 6 carbon atoms, a cycloalkyl group having from 3 to 6 carbon atoms, an alkenyl group having from 2 to 6 carbon atoms, an alkynyl group having from 3 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, a cycloalkoxy group having from 3 to 6 carbon atoms, an alkenyloxy group having from 2 to 6 carbon atoms, an alkynyloxy group having from 3 to 6 carbon atoms, a halogenoalkyl group having from 1 to 6 carbon atoms, a halogenoalkoxy group having from 1 to 6 carbon atoms, an aryl group having from 6 to 12 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom, or an aryloxy group having from 6 to 12 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom, and in a case where R 1 and R 2 each are an alkyl group or an alkoxy group, R 1 and R 2 may bond to form a cyclic structure; R 3 and R 4 each independently represent a hydrogen atom, a halogen atom, or an alkyl group having from 1 to 4 carbon atoms; m indicates an integer of from 1 to 4; n indicates 0 or 1; and q indicates 1 or 2; in case where q is 1 and n is 0, X represents an alkoxy group having from 1 to 6 carbon atoms, an alkynyloxy group having from 3 to 6 carbon atoms, an alkyloxyalkoxy group having from 2 to 6 carbon atoms, an aryloxy group having from 6 to 12 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom; -O-L 1 -OC(=O)-C(=O)-OR 5, -O-L 2 -C(=O)-OR 5, or -O-L 5 -CN; in case where q is 1 and n is 1, X represents an alkyl group having from 1 to 6 carbon atoms, an alkynyl group having from 2 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, an alkynyloxy group having from 3 to 6 carbon atoms, an alkyloxyalkoxy group having from 2 to 6 carbon atoms, or -C(=O)-OR 5; in case where q is 2, X represents -O-L 3 -O-, -OC(=O)-C(=O)O- or a single bond; further, R 5 represents an alkyl group having from 1 to 6 carbon atoms; L 1 and L 3 each represent an alkylene group having from 2 to 6 carbon atoms, or an alkynylene group having from 4 to 8 carbon atoms; L 2 and L 5 each represent an alkylene group having from 1 to 6 carbon atoms; however, when q is 1, n is 0 and X is an alkoxy group having from 1 to 6 carbon atoms, then R 1 and R 2 bond to form a cyclic structure; when q is 1, n is 0 and X is an aryloxy group having from 6 to 12 carbon atoms in which at least one hydrogen atom is substituted with a halogen atom, then R 3 and R 4 are both hydrogen atoms. wherein R 1 and R 2 each independently represent an alkyl group having from 1 to 6 carbon atoms, a cycloalkyl group having from 3 to 6 carbon atoms, an alkenyl group having from 2 to 6 carbon atoms, an alkynyl group having from 3 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, a cycloalkoxy group having from 3 to 6 carbon atoms, an alkenyloxy group having from 2 to 6 carbon atoms, an alkynyloxy group having from 3 to 6 carbon atoms, a halogenoalkyl group having from 1 to 6 carbon atoms, a halogenoalkoxy group having from 1 to 6 carbon atoms, an aryl group having from 6 to 12 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom, or an aryloxy group having from 6 to 12 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom, and in a case where R 1 and R 2 each are an alkyl group or an alkoxy group, R 1 and R 2 may bond to form a cyclic structure; R 3 and R 4 each independently represent a hydrogen atom, a halogen atom, or an alkyl group having from 1 to 4 carbon atoms; m indicates an integer of from 1 to 4; n indicates 0 or 1; and q indicates 1 or 2; in case where q is 1 and n is 0, X represents an alkoxy group having from 1 to 6 carbon atoms, an alkynyloxy group having from 3 to 6 carbon atoms, an alkyloxyalkoxy group having from 2 to 6 carbon atoms, an aryloxy group having from 6 to 12 carbon atoms in which at least one hydrogen atom may be substituted with a halogen atom; -O-L 1 -OC(=O)-C(=O)-OR 5, -O-L 2 -C(=O)-OR 5, or -O-L 5 -CN; in case where q is 1 and n is 1, X represents an alkyl group having from 1 to 6 carbon atoms, an alkynyl group having from 2 to 6 carbon atoms, an alkoxy group having from 1 to 6 carbon atoms, an alkynyloxy group having from 3 to 6 carbon atoms, an alkyloxyalkoxy group having from 2 to 6 carbon atoms, or -C(=O)-OR 5; in case where q is 2, X represents -O-L 3 -O-, -OC(=O)-C(=O)O- or a single bond; further, R 5 represents an alkyl group having from 1 to 6 carbon atoms; L 1 and L 3 each represent an alkylene group having from 2 to 6 carbon atoms, or an alkynylene group having from 4 to 8 carbon atoms; L 2 and L 5 each represent an alkylene group having from 1 to 6 carbon atoms; however, when q is 1, n is 0 and X is an alkoxy group having from 1 to 6 carbon atoms, then R 1 and R 2 bond to form a cyclic structure; when q is 1, n is 0 and X is an aryloxy group having from 6 to 12 carbon atoms in which at least one hydrogen atom is substituted with a halogen atom, then R 3 and R 4 are both hydrogen atoms.