To obtain a method of reducing the FSR and utilizing the refractive index change of PLZT at maximum, and to provide an electrode with a little optical loss and a device with a little wave front deterioration, if PLZT cavity optical switches are arrayed.

A plurality of rectangular parallelepiped cavities 12 are arranged with specified equal pitches in parallel to each other on the upside of a board 11. Electrodes 13, 14 are formed on both lengthwise sides impermeable to light, constituting an optical switch array 10. A plurality of cylindrical lenses 22 are arranged in parallel with the same arranging pitch on a transparent board 21, and the arrays are aligned and laminated together.