Abstract: An image display apparatus has a display device for displaying image information and an optical system for guiding light from the display device to the eye. The optical system has a prism body of a positive refractive power including three or more surfaces with refractive powers differing depending upon azimuthal angles. The surface of the prism body closest to the display device is a surface in which refractive powers thereof differ depending upon azimuthal angles and in which a local curvature radius area having a positive refractive power on a local generating-line section (meridional section) is interposed between local curvature radius areas having a negative refractive power on the local generating-line section (meridional section).