A light deflection element has a pair of transparent substrates 2, 3; a chiral smectic C phase liquid crystal 5 with a homeotropic alignment filled between the pair of transparent substrates 2, 3; and at least an electric field applying device 6 for activating an electric field in the liquid crystal 5. Because a chiral smectic C phase liquid crystal is used, the problems of the conventional light deflection element, such as high cost, light loss, large size, and optical noise etc. due to its complicated structure, can be greatly improved. The conventional low response time due to the smectic A phase or the nematic liquid crystal is improved, thereby the high-speed response is possible.