A liquid-crystal display device has a light pipe, a light source, a reflection polarizer, and a liquid-crystal shutter. The light pipe includes light output means formed on an upper surface of the light pipe. The light source is disposed near to an incident side surface of the light pipe so that incident light from the light source is output from a lower surface of the light pipe through the light output means. The reflection polarizer is disposed on the lower surface of the light pipe for supplying linearly polarized light obtained by reflecting natural light. The liquid-crystal shutter is disposed above the upper surface of the light pipe, the liquid-crystal shutter including liquid crystal cells and at least one polarizing plate.