The present invention relates to a small projection type display unit capable of preventing the overlapping of the optical path of an incident light on that of an outgoing light in a reflection type light bulb and providing high-picture-quality projection images. The projection type display unit comprises an illuminating optical system 2 for collecting light emitted from a light source 1 to form an illuminating light, a reflection type light bulb 6 for reflecting an illuminating light and outputting a modulation light that forms an optical image, a projection lens 7 for projecting an optical image formed by the reflection type light bulb, and a positive-power lens element 5. wherein the lens element (5) has a plurality of projections on one optical interface or both optical interfaces and is placed between the reflection type light valve and the projection lens system so that the illumination light passes through the lens element to illuminate the reflection type light valve, and modulated light output from the reflection type light valve passes through the lens element to be incident upon the projection lens system, and the plurality of projections are formed so that a pitch is [1/2] or less of a visible band wavelength and a height is one time or more of the pitch.