PURPOSE: To prevent leakage current and achieve the reduction of power consumption by bonding an electron blocking layer which blocks the movement of electrons between a solid electrochromic material layer and dielectric layer.

CONSTITUTION: The element is constituted by providing an antireflecting film 6a composed of Al2O3 in adjacency to a glass substrate 1a, then subsequently laminating a transparent electrode 2a, on the one side, composed of In2O3, a dielectric layer 3 composed of NiO, an electron blocking layer 4 composed of Ta2O6, a solid electrochromic material layer 5 composed of WO3, a transparent electrode 2b on the other and antireflecting film 6b and providing a glass substrate 1b by way of an adhesive agent layer 7. If with this constitution the electrodes 2a, 2b of this element are connected respectively to the positive pole and negative pole of a DC power source S, the solid electrochromic material layer 5 and dielectric layer 3 cause oxidation-reduction reaction, thereby forming color. The electron blocking layer 4 blocks the leakage current moving between the electrodes, thereby preventing the increase in power consumption.