NOVELTY - Non-aqueous electrolyte secondary battery comprises a positive electrode plate and a negative electrode plate that contain material able to reversibly absorb and desorb lithium ions; a separator that separates the positive electrode plate and negative electrode plate; and a non-aqueous electrolytic solution in which a solute constituted of lithium salt is dissolved in an organic solvent.    USE - The non-aqueous electrolyte secondary battery is useful as power source for portable electronic equipment such as portable telephones, portable personal computers and portable music players, and further as drive power source for hybrid electric vehicles (HEVs) and electric vehicles (EVs).    ADVANTAGE - The invention provides non-aqueous electrolyte secondary battery that even when stored at high temperature in a charged state is not prone to positive electrode degradation and has a large post-high temperature storage capacity recovery rate and good cycling characteristics.    DETAILED DESCRIPTION - Non-aqueous electrolyte secondary battery comprises a positive electrode plate and a negative electrode plate that contain material able to reversibly absorb and desorb lithium ions; a separator that separates the positive electrode plate and negative electrode plate; and a non-aqueous electrolytic solution in which a solute constituted of lithium salt is dissolved in an organic solvent; the separator being constituted of a polyolefin microporous membrane constituted of two or more layers of stacked film containing polyethylene and polypropylene, one or both of the surface layers having a polypropylene mixture proportion exceeding 50% by mass and containing inorganic particles, and the non-aqueous electrolytic solution containing not less than 0.1% by mass and not more than 3.0% by mass, relative to the mass of the non-aqueous solvent of the non-aqueous electrolytic solution, of a dinitrile compound expressed by CN-(CH2)n-CN, where n is more than or equal to 1 and n is an integer.