PURPOSE: To obtain an optical controller for a liquid crystal-optical shutter which cuts off an incident light beam completely and has the less loss of the quantity of light by sandwiching liquid crystal which has specific refraction characteristics between a couple of bases, and controlling the temperature of this liquid crystal and the angle of incidence of linear polarized light incident to the liquid crystal.

CONSTITUTION: The liquid crystal 3 is arrayed between transparent bases 1 and 2 with a refractive index ng in a homogeneous state to the surface of the base 1. The liquid crystal 3 has a refractive index nc to the incident linear polarized light 9' and the relation of ng to nc at this time is nc<ng. On the other hand, when transparent resistors 4 and 5 are put in anisotropic liquid phase A by conducting electricity to heat up, the refractive index is nISO to the polarized light 9' and nISO<ng. Therefore, the light is made incident to the liquid crystal 3 at the angle θ of incidence within a range sin-1(nISO/ng)≤θ<sin-1(nc/ng); and the transparent resistors 4 and 5 are powered on and off at the same time to transmit the polarized light 9' through the liquid crystal 3 as transmitted light, for example, at the normal temperature or to reflect it totally as totally reflected light 12 in a heating state.