To provide a projection display device capable of smoothly suppressing the lowering of quantity of specified color light or the occurrence of color irregularity even when a display element is shifted relative to the optical axis of a projection optical system so as to shorten a projection distance.

The display elements 16, 19 and 26 are shifted in a Z-axis direction with respect to the optical axis of a dioptric system 30. Thus, the projection distance of a projector can be shortened. A 1/4 wavelength plate 51 changing the polarization direction of light so that the light becomes circularly polarized is arranged between a dichroic prism 27 and the dioptric system 30. Thus, each color light is incident on the dioptric system 30 as circularly polarized light, transmittance of green light in the dioptric system 30 is improved, and the lowering of the quantity of light or the occurrence of color irregularity caused by lowering of the quantity of green light are suppressed.