POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM ION SECONDARY BATTERY AND LITHIUM ION SECONDARY BATTERY

To provide a positive electrode active material capable of further reducing positive electrode resistance and exhibiting better output characteristics. A positive electrode active material includes a coating layer formed of a metal composite oxide of Li and one or more metal elements selected from Al, Ti, Zr, Nb, Mo, and W on at least a part of a surface of lithium transition metal-containing composite oxide particles, and has d50 of 3.0 to 7.0 μm, a BET specific surface area of 2.0 to 5.0 m/g, a tap density of 1.0 to 2.0 g/cm, and an oil absorption amount of 30 to 60 ml/100 g, in which the amount of metal elements other than Li contained in the coating layer is 0.1 to 1.5 atom % with respect to the total number of atoms of Ni, Mn, and Co contained in the composite oxide particles.