An optical element has a fluid container which contains an insulative fluid and a conductive fluid that are different in refractive index from each other, mutually immiscible, and optically transparent, the fluid container being transparent to light at least in a predetermined direction; a first electrode placed in contact with the conductive fluid in the fluid container; multiple transparent second electrodes placed on a transparent surface of the fluid container and insulated from the conductive fluid in the fluid container, with a voltage being applied between the first electrode and each of the multiple transparent second electrodes; and multiple transparent transistors placed on the transparent surface of the fluid container together with the multiple second electrodes to adjust the voltages applied to the multiple second electrodes.