A non-aqueous electrolyte secondary battery which comprises a positive electrode containing a lithium-containing oxide; a negative electrode containing a material capable of absorbing and releasing lithium; and a non-aqueous electrolyte containing a non-aqueous solvent containing at least one non-cyclic ester and which is excellent in storage stability at high temperatures is provided by adding an oxidation resistance improving agent such as triphenylmethane, tetraphehylmethane or the like.