NOVELTY - A nonaqueous electrolyte solution comprises an electrolyte, a nonaqueous solvent, and component(s) (A) chosen from carbon-carbon unsaturated bond-containing carbonate, a cyclic compound (I), sulfoxide, sulfite, sulfone, sulfonate, sultone and sulfate, fluorine-containing cyclic carbonate (B) and compound (C) having at least two isocyanate groups in a molecule, as additional compounds.    USE - Nonaqueous electrolyte solution is used for nonaqueous electrolyte secondary battery (claimed) used as power supply for mobile telephone, laptop computer, motor vehicles, rail vehicles, and load leveling.    ADVANTAGE - The nonaqueous electrolyte secondary battery using nonaqueous electrolyte solution has excellent durability, capacity, output characteristics, thermal stability, high-temperature storing characteristics, and charging/discharging characteristics.    DETAILED DESCRIPTION - A nonaqueous electrolyte solution comprises an electrolyte, a nonaqueous solvent, and component(s) (A) chosen from carbon-carbon unsaturated bond-containing carbonate, a cyclic compound of formula (I), sulfoxide, sulfite, sulfone, sulfonate, sultone and sulfate, fluorine-containing cyclic carbonate (B) and compound (C) having at least two isocyanate groups in a molecule, as additional compounds. The nonaqueous electrolyte solution is used in nonaqueous electrolyte solution secondary battery provided with a positive electrode and a negative electrode which occlude/release a metal ion.    M=-O- or -NR2-;    R2=H or 10C or less optionally branched hydrocarbyl;and    R1=optionally substituted and branched 10C or less hydrocarbyl.    INDEPENDENT CLAIMS are included for the following:    (1) nonaqueous electrolyte secondary battery, which has positive electrode which discharges/occludes lithium ion, negative electrode which discharges/occludes lithium ion, and nonaqueous electrolyte solution; and    (2) positive electrode, which contains lithium manganese complex oxide having layer structure.