The present invention relates to lithium composite oxide particles which can be produced by mixing nickel-cobalt-manganese-based compound particles, a zirconium raw material and a lithium raw material with each other and then calcining the resulting mixture, and comprise a Zr compound that is allowed to be present on a surface thereof, in which the Zr compound is represented by the chemical formula: €ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒ€ƒLi x (Zr 1-y A y )O z wherein x, y and z are 2.0 ‰¤ x ‰¤ 8.0; 0 ‰¤ y ‰¤ 1.0; and 2.0 ‰¤ z ‰¤ 6.0, respectively, and a content of Zr in the lithium composite oxide particles is 0.05 to 1.0% by weight. By using the lithium composite oxide particles as a positive electrode active substance, it is possible to produce a lithium ion secondary battery that has a low electric resistance at a high temperature, and is excellent in cycle characteristic at a high temperature as well as high-temperature rate characteristic.