NOVELTY - Nonaqueous electrolyte secondary battery, comprises: a case (1); a nonaqueous electrolytic solution provided in the case and comprising a nonaqueous solvent and a lithium salt dissolved in the nonaqueous solvent, where the nonaqueous solvent comprises 50-95 vol.% of a sulfone based compound; a positive electrode (3) provided in the case and comprising a composite oxide; and a negative electrode (4) provided in the case and comprising a negative electrode active material which is capable of absorbing and releasing lithium at greater than or equal to 1 V based on a metallic lithium potential.    USE - The nonaqueous electrolyte secondary battery is useful in a battery pack (claimed) in digital cameras, cars, two to four wheeled hybrid battery automobiles, two to four-wheeled battery automobiles and motor assisted bicycles.    ADVANTAGE - The nonaqueous electrolyte secondary battery has improved battery properties and cycle performance.    DETAILED DESCRIPTION - Nonaqueous electrolyte secondary battery, comprises: a case; a nonaqueous electrolytic solution provided in the case and comprising a nonaqueous solvent and a lithium salt dissolved in the nonaqueous solvent, where the nonaqueous solvent comprises 50-95 vol.% of a sulfone based compound of formula (R1-S(=O)2-R2); a positive electrode provided in the case and comprising a composite oxide of formula Li1-xMn1.5-yNi0.5-zQy+zO4; and a negative electrode provided in the case and comprising a negative electrode active material which is capable of absorbing and releasing lithium at greater than or equal to 1 V based on a metallic lithium potential.    R1, R2 = 1-6C alkyl (methyl, ethyl, butyl or isopropyl), where R1 is not same as R2;    x = 0-1;    y+z = 0-0.15; and    Q = Mg, Al, Ti, Fe, Co, Ni, Cu, Zn, Ga, Nb, Sn, Zr or Ta.    DESCRIPTION OF DRAWING(S) - The figure shows a schematic view showing the cross-section of a nonaqueous electrolyte secondary battery.    Case (1)    Positive electrode (3)    Negative electrode (4)    Separator (5)    Belt-shaped positive electrode terminal (6)