The present invention is to provide a cathode active material configured to increase, when used in a lithium battery, the discharge capacity of the lithium battery higher than conventional lithium batteries, and a lithium battery including the cathode active material. Presented is a cathode active material for lithium batteries, wherein the cathode active material is represented by the following composition formula (1) and has a rock salt type crystal structure including formula (1): Li2Ni1-x-yCoxMnyTiO4 wherein x and y are real numbers that satisfy x>0, y>0 and x+y<1.