FLEXIBLE ELECTROCHROMIC DEVICE

The embodiments relate to an electrochromic device having flexibility while achieving an excellent light transmission variable function based on the electrochromic principle. The electrochromic device comprises a light transmission variable structure interposed between a first base layer and a second base layer, wherein the light transmission variable structure comprises a first chromic layer and a second chromic layer, and the value of ΔTTdas defined in Equation (1) is 3% or less.