A lithium ion secondary battery has a battery can, an electrode assembly in the battery can formed by rolling up a positive electrode, a separator, and a negative electrode, an organic electrolyte solution in the battery can, a positive electrode lead in the battery can connected to the positive electrode, a negative electrode lead in the battery can connected to the negative electrode, an overcharge preventer, a cap body sealing the battery can, a positive electrode terminal fixed to the cap body and connected to the positive electrode lead, and a negative electrode terminal fixed to the cap body and connected to the negative electrode lead.