Abstract: A projection type image display apparatus makes illumination light from a light source section incident on a rectangular reflection type liquid crystal display device by way of a polarization beam splitter, optically modulates the illumination light in the reflection type liquid crystal display device, and projects thus modulated light through a projection lens by way of the polarization beam splitter. A plane including the optical axis of illumination light incident on the polarization beam splitter and the optical axis of illumination light emitted from the polarization beam splitter toward the projection lens is substantially parallel to a direction in which a shorter side of the reflection type liquid crystal display device extends.