Electric double-layer capacitor

An electric double-layer capacitor comprising:

• a positive electrode including a positive-electrode collector electrode and a positive-electrode polarizable electrode provided on the positive-electrode collector electrode;
• a negative electrode including a negative-electrode collector electrode and a negative-electrode polarizable electrode provided on the negative-electrode collector electrode, the negative electrode facing the positive electrode such that the positive-electrode polarizable electrode and the negative-electrode polarizable electrode oppose each other;
• an electrolyte interposed between the positive electrode and the negative electrode;
• and
• a flat, plate-shaped separator between the positive-electrode polarizable electrode and the negative-electrode polarizable electrode,
• wherein, in a thickness direction of the electric double-layer capacitor, an outermost electrode of either the positive electrode or the negative electrode does not have the polarizable electrode on an outer surface of either the positive-electrode collector electrode or the negative-electrode collector electrode.