A projection-type liquid crystal display device having a light source for emitting a luminous flux; a liquid crystal light valve for modulating the luminous flux emitted by the light source means; a liquid crystal drive circuit for applying the common voltage to the common electrode and the video signal to the source electrode; a projection lens for projecting the luminous flux modulated by the liquid crystal light valve onto a screen; a liquid crystal temperature detector for detecting temperature in the vicinity of the liquid crystal light valve; and a controller. The controller controls the common voltage and/or the source voltage on the basis of values detected by the liquid crystal temperature detector in such a way that fluctuation in the light transmittance of the liquid crystal light valve means is reduced.