PURPOSE: To prevent generation of an interference fringe, by eliminating or suppressing a reflection itself of read-out light in the inside of a picture converting (ITC) element.

CONSTITUTION: Light L3 reflected by a surface 13 by utilizing a tansparent substrate, etc. being an entity of an ITC element itself is not reflected by the other surface 10 of the element body, but is made to pass through the transparent substrate 1 again and is emitted to the outside of the ITC element as shown by a broken lineI5. A surface 3 of a crystal plate 2 is polished, the first transparent electrode 4 is vapor-deposited, and also the transparent substate 1 is junctioned by an optical adhesive agent 5. After that, the other surface 6 of the crystal plate 2 is polished to prescribed thickness, and a layer-like transparent insulator 7 and the second transparent electrode 8 are formed. As for the crystal plate 2, a crystal having both an electro-optical effect and a photoelectric effect depending on the wavelength, such as a bismuth silicon oxide monocrystal or a bismuth germanium oxide monocrystal, etc. is used, and its surfaces 3, 6 are made parallel to each other.