Disclosed herein is an electrochromic display device comprising a pair of transparent substrates facing each other, an anode electrode and a cathode electrode respectively formed on the transparent substrates, an electrolytic layer disposed between the anode electrode and the cathode electrode, an electrochromophore layer of a nano structure formed on at least one of the anode electrode and the cathode electrode, and a redox promoter layer coated with a conductive compound, on the other electrode.