A high-quality electrochemical optical device includes: first and second substrates having electrodes so that the electrodes of the second substrates are arranged to correspondingly face the electrodes of the first substrate; reaction/ion conduction layers each disposed between one electrode of the first substrate and a corresponding one electrode of the second substrate; and conduction materials disposed between the first and second substrates and between the reaction/ion conduction layers. Electrochemical optical element regions are defined in a tiling fashion at respective positions of the reaction/ion conduction layers to correspondingly include the electrodes of the first and second substrates, and the reaction/ion conduction layer. The conduction materials electrically connect the electrochemical optical element regions in series in the same direction by connecting the electrode of the first substrate in one of the mutually adjacent electrochemical optical element regions and the electrode of the second substrate in the other electrochemical optical element region.