With the aim of offering a video display technique by which stable and high contrast video images are reproduced, contrast adjusting circuitry is constructed. The contrast adjusting circuitry detects a maximum picture level (MPL) and an average picture level (APL) of analog-to-digital converted luminance signals for a predetermined period, determines one of the predefined luminance regions within which the MPL falls and one of the predefined luminance regions within which the APL falls, and, based on the thus determined luminance regions of both MPL and APL, carries out a contrast adjustment of video images by changing the gain of luminance signals and color depth correction by changing the gain of color signals.By means of the illuminating optics and color synthesis optics of a projector using three video display elements, alleviating color heterogeneity and uneven luminance and offering high contrast images are achieved at reduced cost, and the convergence drift of an enlarged image displayed on the screen can be alleviated.