Electrochromic display device manufacture method wherein electrochromic material is deposited in a single layer on a single film of conductive material over the whole area of glass substrate and then the electrochromic material and conductive material are successively etched through a single mask which defines a display segment pattern and remains in position throughout the whole etching process, whereby etched edge portions of the different materials are in excellent alignment and there is therefore small plate area for a reverse emf cell and good display device performance is achieved. The electrochromic material may be etched by the solution employed for developing the photoresist, whereby an etching process step is eliminated.