A lithium ion secondary battery includes an electrode group formed by winding a positive electrode having a positive electrode current collector and a positive electrode active material layer, and a negative electrode having a negative electrode current collector and a negative electrode active material layer, with a separator interposed between the electrodes. A wound positive electrode current collector exposing section faces a wound negative electrode current collector exposing section with the separator interposed therebetween, thereby forming a heteropolar electrode current collector facing zone corresponding to at least one turn in the electrode group. A unipolar electrode current collector facing zone, in which adjacent portions of the wound current collector exposing section or the wound current collector exposing section face each other directly or with the separator interposed therebetween corresponds to at least one turn in the electrode group.