A lithium ion secondary battery includes: a positive electrode including a positive electrode active material layer; a negative electrode; and an electrolyte. The positive electrode active material layer contains Lia(M)b(PO4)c (M=VO or V, 0.9≦a≦3.3, 0.9≦b≦2.2, 0.9≦c≦3.3) as a first positive electrode active material, and additionally contains a fluorine compound of 1 to 300 ppm in terms of fluorine with respect to a weight of the positive electrode active material layer.