Present invention relates to an electric double-layer capacitor having
positive and negative electrodes containing nonporous carbon as an
electrode active material. In the nonporous carbon, multiple layers of
graphene having an average interplanar spacing d.sub.002 of 0.350 to
0.380 nm have been grown well. The positive and negative electrodes are
impregnated with an electrolyte solution. The nonporous carbon is
obtained by activating easily graphitizable carbon, which in turn is
obtained by calcining needle coke or pitch made infusible. The elctrolyte
solution is either a liquid electrolyte having a planar molecular
structure or an electrolyte solution consisting of a liquid electrolyte
dissolved in an organic solvent.