An electric double layer capacitor has a pair of current collectors, a positive polarizable electrode which is provided on one of the pair of current collectors, includes activated carbon of a weight W+ and has a capacitance C+, a negative polarizable electrode which is provided on the other of the pair of current collectors, includes activated carbon of a weight W− and has a capacitance C−, a separator interposed between the positive and negative polarizable electrodes, and an organic electrolytic solution which impregnates at least the positive and negative polarizable electrodes and the separator, wherein C−/C+=0.6 to 1.0 and W−/W+=1.1 to 2.0. Even when continuously charged at a high applied voltage, the electric double layer capacitor has a high retention of capacitance and a low rise in internal resistance, and thus has an excellent durability.