A non-aqueous electrolyte secondary battery of the present invention includes a positive electrode including a positive electrode material mixture, a negative electrode including a negative electrode material mixture, and a non-aqueous electrolyte including a non-aqueous solvent and a first lithium salt and a second lithium salt dissolved in the non-aqueous solvent. The negative electrode material mixture includes a material capable of absorbing and desorbing lithium ions, and carbon nanofibers. The material capable of absorbing and desorbing lithium ions has a ratio A/B of a volume A in a charged state to a volume B in a discharged state of 1.2 or more. The first lithium salt is at least one selected from the group consisting of LiBF.sub.4 and LiB(C.sub.2O.sub.4).sub.2. The second lithium salt is a salt other than the first lithium salt. The first lithium salt is included in the non-aqueous electrolyte at a weight ratio of 10.sup.-4 or more relative to the carbon nanofibers. The first lithium salt included in the non-aqueous electrolyte has a concentration of 0.05 mol/dm.sup.3 or less.