PURPOSE: To solve defects of the oxidative coloring type ECD element such as a late response rate, and a short life due to an undesired side reaction etc. by providing a colorless or a pale colored reversible electrolytic reduction layer to the titled element.

CONSTITUTION: The titles element is constituted of the oxidative coloring type ECD layer 1, the colorless or the pale colored reversible electrolytic reduction layer 2 and a pair of electrodes 3a, 3b, The colorless or the pale colored reversible electrolytic reduction layer 2 is a dispersion obtd. by diluting an iridium oxide or hydroxide with an inactive dispersion medium. The content of the Ir metal is preferable to be 3W10at%. The transparent inactive dispersion medium is comprised for example, a slicon oxide.