The present invention improves the cycle characteristics of a non-aqueous electrolyte secondary cell that uses lithium cobalt oxide as a positive electrode active material. To this end, an element different from cobalt such as zirconium and titanium is added to the lithium cobalt oxide, acting as the positive electrode active material. The non-aqueous electrolyte contains a non-aqueous solvent containing diethyl carbonate at 10 to 30 volume percent on a base of 25 degree Celsius and contains an electrolyte salt.