METHOD OF MANUFACTURING POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM ION SECONDARY BATTERY, POSITIVE ELECTRODE ACTIVE MATERIAL FOR LITHIUM ION SECONDARY BATTERY, AND LITHIUM ION SECONDARY BATTERY

A method of manufacturing a positive electrode active material for a lithium ion secondary battery includes a mixing step of mixing a lithium-nickel composite oxide which is a starting material with a tungsten compound powder without lithium, while being heated, to prepare a tungsten mixture, and a heat treatment step of heat-treating the tungsten mixture. The lithium-nickel composite oxide contains lithium (Li), nickel (Ni), and an element M (M), wherein, the element M is at least one element selected from Mn, V, Mg, Mo, Nb, Ti, Co, and Al, wherein, in the starting material, a ratio of number of tungsten atoms to a total number of nickel atom and the element M atoms contained in the lithium-nickel composite oxide is 0.05 at. % or more and 3.00 at. % or less.