The invention relates to a projection viewing system of simplified construction and high illumination efficiency, which enables at least two of images varying with viewing directions to be simultaneously displayed in a viewable fashion. The system comprises at least two display devices 11 and 12, at least two projection optical systems 21 and 22 for magnifying and projecting images appearing on the display devices 11 and 12, a common diffusing plate 4 located near to images projected through the projection optical systems 21 and 22 and a common eyepiece optical system 3 for projecting exit pupils of the projection optical systems 21 and 22 on the eyeballs E1 and E2 of viewers.