A liquid crystal display device in which light from a light source enters a liquid crystal panel and exits therefrom for projection of an image and includes a heat conducting member and a cooling unit. The heat conducting member is contacted with at least one of a light incident surface and a light outgoing surface of the liquid crystal panel, is light-transmissive, and has a larger area than a light transmitting area of the liquid crystal panel. The cooling jacket, which comprises a flow channel for a cooling medium in its inside, is provided around the heat conducting member so that the flow channel exists only outside of the light transmitting area in a surface direction of the liquid crystal panel.