In this work some electrochemical characteristics of all solid double layer capacitors prepared by high surface carbon and Nafion polymer electrolyte are reported. Carbon composite electrodes with a Nafion loading of 30wt.% were prepared and evaluated. Nafion 115 membrane, recast Nafion membrane and 1M H2SO4 solution in a matrix of glass fiber have been used as electrolyte, in the double layer capacitors. The different double layer capacitors (DLCs) have been evaluated by electrochemical impedance spectroscopy. The capacitor with a recast Nafion electrolyte exhibits a proton conductivity of about 3×10−2 Scm−1 at ambient temperature, that is higher of that reported for solid electrolytes (10−3 to 10−4 Scm−1) in the current literature on capacitors. A maximum of specific capacitance of 13F/g of active materials (carbon+Nafion) corresponding to 52F/g for a single electrode measured in a three-electrode arrangement has been achieved with the capacitor with recast Nafion. The capacitance of the capacitor with recast Nafion electrolyte, evaluated in low-frequency region below 10mHz, was practically equivalent at that with sulphuric acid electrolyte. The interpretation of the characteristics of the microporous structure of carbon material of the electrodes by impedance analysis is also discussed.