To provide a small-size projection type display which prevents generation of a ghost image.

Two triangular prisms having the cross-sectional form of right-angle triangles are adhered to each other with a polarization separation film interposed to constitute each polarization beam splitter 20G to 20R. Two apex angles except for the right angle of the right-angle triangle are an apex angle α of smaller than 45° and an apex angle β of larger than 45°. The B light and the mixed light of R light and G light separated by dichroic mirrors 16RG and 16B are reflected by reflecting and bending mirrors 18, 17 to be converged nearer to each other. When the light from a light source 11 is made to enter the polarization beam splitters 20R to 20G, the incident angle of the axis of the incident light on each entrance face of the polarization beam splitters 20G to 20R is controlled to a specified angle θ (shown in Fig.2) so that the light enters each polarization separation part of the polarization beam splitters 20R to 20G at the incident angle equal to the apex angle α. The entrance faces of polarization beam splitter 20G to 20R where the light from the light source enters, and the optical axes of the light reflected and exiting from light valves 21R to 21G are controlled to be parallel to each other, respectively.