A positive electrode material for a lithium secondary battery for high voltage high capacity use exhibiting high cycle durability and high safety. The positive electrode material is composed of particles having a composition represented by the general formula: Li.sub.aCo.sub.bMg.sub.cA.sub.dO.sub.eF.sub.f (A is the group 6 transition element or the group 14 element, 0.90.ltoreq.a.ltoreq.1.10, 0.97.ltoreq.b.ltoreq.1.00, 0.0001.ltoreq.c.ltoreq.0.03, 0.0001.ltoreq.d.ltoreq.0.03, 1.98.ltoreq.e.ltoreq.2.02, 0.ltoreq.f.ltoreq.0.02 and 0.0001.ltoreq.c+d.ltoreq.0.03), and magnesium, the element A and fluorine exist uniformly in the vicinity of the surfaces of the particles.