An electric double layer capacitor in which gas generation due to decomposition of a solvent of an electrolyte solution in the capacitor is reduced and performance maintaining ratio is superior, is provided by a method which is different from a method of adding additives to the electrolyte solution. The electric double layer capacitor has activated carbon polarizing electrodes and a non-water-based solvent, and a positive electrode of the activated carbon polarizing electrodes contains an antacid agent.