NOVELTY - A positive electrode active material comprises lithium-nickel-manganese-cobalt-iron oxide complex (I). The positive electrode active material has rock-salt-type layer structure and exhibits diffraction peak at angle of 20-23 degrees , 35.5-36.5 degrees (101), 43.5-44.5 degrees (104), and 64-65(108)/65-66(110), measured in X-ray-diffraction measurement.    USE - Active material is used for positive electrode for nonaqueous electrolyte secondary battery (all claimed). Uses include but are not limited to electronic device, hybrid vehicle, electric vehicle and fuel cell electric vehicle.    ADVANTAGE - The elution of transition metal, preferably manganese in positive electrode active material is suppressed by using iron as a substituted element. The nonaqueous electrolyte secondary battery provided with positive electrode obtained using the active material has excellent cycle characteristics.    DETAILED DESCRIPTION - A positive electrode active material comprises lithium-nickel-manganese-cobalt-iron oxide complex of formula: Li1.5(NiaMnbCoc(Li)d(X)eFef)Oz (I), where X is titanium, zirconium, niobium or tin, f is 0.1-0.2, e+f is 0.01-0.2, preferably 0.02-0.15, a+b+c+d+e+f is 1.5, d is 0.1-0.4, a+b+c+e+f is 1.1-1.4 and z is number of oxygen. The positive electrode active material has rock-salt-type layer structure and exhibits diffraction peak at angle of 20-23 degrees , 35.5-36.5 degrees (101), 43.5-44.5 degrees (104), and 64-65(108)/65-66(110), measured in X-ray-diffraction measurement. INDEPENDENT CLAIMS are included for the following:    (1) manufacture of positive electrode active material, which involves spray-drying raw material mixed solution in which aqueous medium is dissolved, obtaining dried material, thermally decomposing at least one portion of salt in the resultant dried material obtaining precursor and baking the precursor at 400-1000 degrees C. The raw material mixed solution comprises citrate and/or nitrate of iron, titanium, zirconium, niobium and tin, and organic acid salt of nickel, manganese and cobalt, and/or lithium nitrate;    (2) positive electrode; and    (3) nonaqueous electrolyte secondary battery.