A secondary battery includes an electrode, a positive electrode current collector, a negative electrode current collector, a positive electrode terminal, a negative electrode terminal, and an insulating plate. The positive electrode terminal and the negative electrode terminal each have a main side surface and a sub side surface having an area smaller than that of the main side surface. The positive electrode terminal and the negative electrode terminal are arranged so that the main side surface of the positive electrode terminal and the main side surface of the negative electrode terminal face each other. The insulating plate is arranged between the main side surface of the positive electrode terminal and the main side surface of the negative electrode terminal.