To produce activated carbon for an electrode of an electric double-layer capacitor, the following steps are carried out sequentially: a step of subjecting a massive mesophase pitch to a pulverizing treatment to provide a pulverized powder; a step of subjecting the pulverized powder to an infusibilizing treatment under conditions of a temperature in a range of 300.degree. C. (inclusive) to 450.degree. C. (inclusive) in the atmospheric air current, a step of subjecting the pulverized powder to a carbonizing treatment under conditions of a temperature in a range of 600.degree. C. (inclusive) to 900.degree. C. (inclusive) in an inert gas current to provide a carbonized powder, a step of subjecting the carbonized powder to an alkali activating treatment under conditions of a temperature in a range of 500.degree. C. (inclusive) to 1,000.degree. C. (inclusive) in an inert gas atmosphere, followed by the post treatments, thereby producing alkali-activated carbon, and a step of subjecting the alkali-activated carbon to a pulverizing treatment. If an electrode is produced using the activated carbon, the electrode density can be increased.