To provide a positive electrode active material having high capacity and capable of obtaining superior characteristics even under a high-temperature environment, a positive electrode using this and a non-aqueous electrolyte battery.

The positive electrode 21 has a positive electrode active material. The positive electrode active material exists in a morphology in which fluorine (F) is solid solution substituted to lithium transition metal compound oxide particles. Furthermore, at least nickel (Ni) and manganese (Mn) exist excessively on the surface of the particles compared with the total particles, and the element composition on the surface of the particles becomes 0.01F/O21 and (Co/[Ni+Mn])4.5.