PURPOSE: To easily obtain an electrochromic display device having the excellent quality of display, by forming a display electrode, i.e., an oxide thin film which is obtained by coating a transition metallic compound solution on a substrate and then drying and heating said compound solution.

CONSTITUTION: An aqueous solution of a transition metallic compound like metatungsten acid[H6(H2W12O40)], etc. is coated on a transparent electrode film 2 provided on a substrate 1. The substrate 1 is dried and heated up to 150W 170°C to form a transition metallic oxide film 3 like WO3, etc. This film 3 is used as a display electrode which is used to an electrochromic display device. This display electrode has the performance equal to or higher than an electrode formed by a conventional vapor-deposition process in terms of response speed, coloring efficiency, etc.