An electrochromic device, the electrochromic device including a substrate; a first electrode provided on the substrate; an ion storage layer provided on the first electrode; a polymer electrolyte layer provided on the ion storage layer; an electrochromic layer provided on the polymer electrolyte layer; and a second electrode provided on the electrochromic layer, wherein the ion storage layer includes MoaTibOxNy, and a, b, x and y are the same as or different from each other and each independently is a real number of greater than or equal to 0.5 and less than or equal to 60. Also included is a method for manufacturing an electrochromic device.