NOVELTY - An electrode (10a, 10b) for a capacitor comprises activated carbon; and 25 to 75 parts by weight of carbon aerogel per 100 parts by weight of the activated carbon. The diameter ratio of the carbon aerogel to the activated carbon is 0.4 to 0.8. The electrode for a capacitor further comprises 5 to 25 parts by weight of ketjen black per 100 parts by weight of the activated carbon. The diameter ratio of the ketjen black to the activated carbon is 0.1 to 0.6. The electrode for a capacitor further comprises a polymer binder.    USE - As electrode for a capacitor such as electric double layer capacitor (claimed); as auxiliary power sources for cellular phones, auxiliary batteries for electric cars and auxiliary battery for solar cells.    ADVANTAGE - The electrode has excellent bonding strength between electrode materials and is free of defects such as aggregation and cracking. The electric double layer capacitor having this electrode has high capacitance and low internal resistance. The capacitor containing the electrode exhibits faster charging times, offer longer life, allow for higher power output and has higher energy density.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following:    (1) manufacturing an electrode for a capacitor involving mixing an active material comprising 10 to 30 parts by weight of activated carbon and carbon aerogel, 1 to 5 parts by weight of polymer binder, and 60 to 80 parts by weight of solvent to obtain a mixture; and coating metallic foil with the mixture and drying the metallic foil coated with the mixture; and    (2) an electric double layer capacitor comprising first and second electrodes containing activated carbon and 25 to 75 parts by weight of carbon aerogel per 100 parts by weight of the activated carbon; an ion permeable separation membrane (30) provided between the first and second electrodes; and an electrolyte with which the first and second electrodes are impregnated. The first and second electrodes further comprise 5 to 25 parts by weight of ketjen black per 100 parts by weight of the activated carbon.    DESCRIPTION OF DRAWING(S) - The figure shows cross-sectional view schematically illustrating an electric double layer capacitor.    First electrode (10a)    Second electrode (10b)    First collector (20a)    Second collector (20b)    Ion permeable separation membrane (30)    First metal case (40a)    Second metal case (40b)    First gasket (50a)    Second gasket (50b)