A positive electrode for a lithium-ion secondary cell is provided including a collector and a positive electrode active material layer on the collector, wherein: the positive electrode active materiallayer includes a positive electrode active material, a conductive aid, and a binder; the positive electrode active material layer has a porosity of 20% or less; the positive electrode active materialincludes a lithium composite oxide; the positive electrode active material has a BET specific surface area of 0.1-1 m2/g, at least some of the conductive aid comprises spherical amorphous carbon particles; and the conductive aid content is 1.8-6 mass% in relation to the positive electrode active material.