A first cathode lead terminal is arranged closer to one end of a cathode foil than a second cathode lead terminal, and a first anode lead terminal is arranged closer to one end of an anode foil than a second anode lead terminal. In a cross-section perpendicular to an axis, a core has a first length along a first straight line passing through the axis and a second length along a second straight line passing through the axis and orthogonal to the first straight line, and the first length is smaller than the second length. When the cathode and the anode foils are together wound around the core from each one end, the first straight line lies between the first cathode lead terminal and the first anode lead terminal and the second straight line lies between the second cathode lead terminal and the second anode lead terminal.