To realize a small-sized inexpensive device having good contrast in the case of enlarging and displaying an image on a screen, etc., as for a projection type image display device using a reflection type display element.

The projection type image display device is constituted of a light source part for emitting white light, an illuminating optical system for guiding the light emitted from the light source part, the reflection type display element arranged in the illuminating position of the illuminating optical system, and projection lens for enlarging and projecting the image on the reflection type display element. The light of pixels unnecessary to form the image reflected by reflection type display element is prevented from falling on the projecting lens by a gel-like member arranged on the illuminating optical system.