A cathode active material includes a first cathode material configured of a layered rocksalt type lithium metal oxide, the layered rocksalt type lithium metal oxide including lithium and a metal other than lithium, the metal configured of nickel (Ni), or nickel (Ni) and the like. A site occupancy of metal ions other than lithium at a 3a site obtained by Rietveld analysis of a powder X-ray diffraction pattern of the first cathode material in a cathode in a discharged state is about 5% or less, and a site occupancy of metal ions other than the metal occupying a part of a 3b site at the 3b site is about 1% or over, and the cathode active material is covered with a coating film, and an exposed amount of the cathode active material exposed from the coating film is within a range from about 0.05% to about 8% both inclusive.