Abstract : Well-ordered nanoporous alumina templates were fabricated by two-step anodization method by applying a constant voltage of 40 V in oxalic acid solution or of 25 V in sulfuric acid solution. The cylindrical pore diameter and pore density of the templates utilized for the carbon nanotube (CNT) growth were 86 짹 5 nm and 1.2 쨌 1010 cm2 in oxalic acid solution and 53 짹 1 nm and 3.1 쨌 1010 cm2 in sulfuric acid solution, respectively. The CNTs with uniform diameter of 50 짹 10 nm (oxalic acid) and 44 짹 2 nm (sulfuric acid) were grown on the porous alumina template as electrode materials for the electrochemical double layer capacitor (EDLC). The EDLC characteristics were examined by measuring the capacitances from cyclic voltammograms and the charge