A projection display apparatus includes a reflective image display element having an image display surface including micromirrors, a prism unit bending an optical path of illumination light and transmitting image light, and a projection optical system. The prism unit has an air gap tilted with respect to a principal ray of the image light emitted from the center of the image display surface, and the image light passes through the air gap. The projection optical system includes an aperture stop with a noncircular aperture so shaped that part of a circular aperture in a peripheral portion thereof is cut off in a shape of a segment to serve as a shade portion, and image light corresponding to an end portion at a side where an incidence angle with respect to the air gap is large in an F-number beam is blocked by the shade portion satisfying predetermined conditions.