A liquid crystal optical device comprising a pair of substrates provided with electrodes and a layer containing a liquid crystal material sandwiched between the pair of substrates, wherein said layer is formed by irradiating light to a mixture of a liquid crystal material and a photo-curable compound selected so that the refractive index of the resulting cured product agrees to either the ordinary refractive index (n.sub.O) or the extraordinary refractive index (n.sub.e) of the liquid crystal material used, or the refractive index (n.sub.x) of the liquid crystal material when it is randomly oriented, held between the pair of substrates provided with electrodes, to cure the photo-curable compound and fix the resulting phase separation of the liquid crystal material and the cured product, wherein said layer has at least a portion optically oriented by applying a voltage to the portion across the substrates during the irradiation of light to cure the photo-curable compound.