The inorganic electrochromic display device used tungsten oxide thin film on indium-tin oxide trans-parent electrode as a display electrode. Display electrode was made by rf-sputtering and evaporation methods. The characteristics of electrochromic display device such as response time, memory time, stability, coloration and bleach were studied. When display electrode was colored and bleached in the liquid electrolyte of lithium salt-organic solvent, the color-ing current and bleaching current of display electrode were increaaed by increasing the amount of water in electrolyte. The optical density and response rate of ECD cell were enhanced by depositing SiO₂ film between WO₃ film and MgF₂ film, and decreasing the leak current. In the case of ECD cell with two coloring layers, gas evolution was suppressed and the degree of coloration was en-hanced below -3.0V. In the case of using LiF solid electrolyte, the response rate and memory characteristics were ex-cellent, but bleaching was poor as the number of coloration and bleaching cycle increases.