A non-aqueous electrolyte secondary battery provided with a positive electrode having a lithium-manganese composite oxide as a positive electrode material, a negative electrode comprising a material capable of absorbing and releasing lithium and a non-aqueous electrolyte can be inhibited from deterioration of the negative electrode and can maintain excellent battery performances even after stored in a high-temperature environment or subjected to charging and discharging cycles at high temperatures by containing at least one of sodium (Na), potassium (K), calcium (Ca) and strontium (Sr).