A positive electrode active material includes: a lithium complex oxide expressed by chemical formula (1); a highly thermal conductive compound; and graphene or multilayer graphene. LixM1yM21-yO2  (1) In the formula (1), M1 is at least one metal selected from Ni, Co, and Mn, M2 is at least one metal selected from the group consisting of Al, Fe, Ti, Cr, Mg, Cu, Ga, Zn, Sn, B, V, Ca, and Sr, and x and y are numbers such that 0.05≤x≤1.2 and 0.3≤y≤1.