Disclosed is a positive electrode active material for a nonaqueous electrolyte secondary battery containing at least a lithium-transition metal composite oxide of a spinel structure, in which at least one kind of element which may become tetravalent exists on at least a surface of the lithium-transition metal composite oxide, and concentration of the element which may become tetravalent on the surface of the lithium-transition metal composite oxide is higher than concentration of the element which may become tetravalent inside the lithium-transition metal composite oxide. A use of this positive electrode active material can improve cycle characteristics and high rate characteristics without reducing the charge-discharge capacity of the lithium-transition metal composite oxide.