A positive electrode collector includes a main body layer and a surface layer. The surface layer is provided at least at a portion of a surface of the main body layer where the positive electrode mixture layer is provided, and is made of a carbon material. A first positive electrode active material is made of first lithium complex oxide having a layered crystal structure. A second positive electrode active material includes a particle made of second lithium complex oxide having an olivine crystal structure, a carbon film provided at least at a part of a surface of the particle, and alginic acid salt provided at least at a part of a surface of the carbon film. A conducting agent in the positive electrode mixture layer includes a carbon particle and alginic acid salt provided at least at a part of a surface of the carbon particle.