For dissolving ununiformity in the brightness of a projection image within a display image apparatus, obtaining an enlarged projection image through an oblique projection of image lights onto a rear-surface projection type screen, wherein an image from an image generating source 1 is projected through a projection optical system, having a projection lens 2, curved surface reflection mirrors 4 and 5, a reflection mirror 6, from a rear surface of the rear-surface projection type screen 3, within a housing 7 being narrow in depth thereof; the rear-surface projection type screen includes a Fresnel lens sheet 8, wherein the prism surfaces of the Fresnel lens making up the Fresnel lens sheet are formed in an aspheric configuration, thereby letting the light beams from the screen to exit at an exit angle of about zero (0) degree, almost all over the entire surface thereof. With this, it is possible to obtain a projection image, being uniform in the brightness thereof as a whole, and thin-sizing of the image display apparatus, as well.