A non-aqueous electrolyte secondary battery includes a positive electrode containing a positive electrode active material; a negative electrode containing a negative electrode active material; and a non-aqueous electrolyte containing a non-aqueous solvent and an electrolyte salt. In order to improve the high-temperature storage characteristics and safety against overcharge due to high-rate charging of the battery, the positive electrode active material contains a layered lithium-transition metal composite oxide containing at least one of Mg, Al, Ti, and Zr. Furthermore, the non-aqueous electrolyte contains 3 to 80% by mass of a tertiary carboxylic acid ester expressed by Chemical Formula 2 below, based on the total mass of the non-aqueous solvent: ##STR00001## where R1 to R4 are independent of each other and each represents an alkyl group having 4 or less carbon atoms and being able to be branched.