A cathode material with excellent capacity and output characteristics and safety, and a lithium ion secondary battery using the same is provided. The invention relates to a cathode material which includes a mixture of a cathode active material having a large primary particle size with excellent capacity characteristics and represented by the composition formula: Lix1Nia1Mnb1Coc1O2, where 0.2≦x1≦1.2, 0.6≦a1, 0.05≦b1≦0.3, 0.05≦c1≦0.3, and another cathode active material having a small primary particle size with excellent output characteristics and represented by the composition formula: Lix2Nia2Mnb2Coc2O2, where 0.2≦x2≦1.2, a2≦0.5, 0.05≦b2≦0.5, 0.05≦c2≦0.5. The invention also relates to a lithium ion secondary battery using the cathode material.