NOVELTY - Nickel compound, cobalt compound and manganese compound are mixed in a solvent till the mean particle diameter of the slurry is 0.1-1 mu m. The obtained slurry is spray-dried. The mean particle diameter of the dried material is 2-6 mu m. The resultant product is baked, to obtain lithium-nickel-cobalt-manganese oxide composite. The obtained lithium-nickel-cobalt-manganese composite is washed using water and vacuum-dried, to obtain positive electrode active material having layer structure.    USE - Manufacture of positive electrode active material used for positive electrode of nonaqueous electrolyte secondary battery e.g. 2032-type coin battery (all claimed) and lithium secondary battery. Uses include but are not limited to motor vehicle, electric vehicle, hybrid vehicle, mobile telephone and notebook computer.    ADVANTAGE - The battery obtained using the positive electrode active material has high-initial stage discharge capacity, low resistance and excellent electrical property.    DETAILED DESCRIPTION - Nickel compound, cobalt compound and manganese compound are mixed in a solvent till the mean particle diameter of the slurry is 0.1-1 mu m. The obtained slurry is spray-dried. The mean particle diameter of the dried material is 2-6 mu m. The resultant product is baked, to obtain lithium-nickel-cobalt-manganese oxide composite of formula: LiwNixCoyMnzO2. The obtained lithium-nickel-cobalt-manganese composite is washed using water and vacuum-dried, to obtain positive electrode active material having layer structure.    w=0.95-1.05;    x,z=0.3-0.45, wherein x and z are same;    y=0.1-0.4;and    x+y+z=1.    An INDEPENDENT CLAIM is included for positive electrode active material. The site occupation rate of metal ions other than lithium in 3a site of the positive electrode active material is 5% or less, measured by Rietveld analysis of a powder X-ray-diffraction pattern. The site occupation rate of metal ions other than nickel, cobalt and manganese in 3b site of the positive electrode active material is 10% or less, measured by Rietveld analysis of a powder X-ray-diffraction pattern.