A head-up display apparatus projects a display image onto a projection surface of a windshield so that a viewer views a virtual image of the display image from an eye box. A screen used in the apparatus is constructed of a plurality of micromirrors. Each micromirror has a convex surface portion being curved to magnify a laser beam toward the eye box. A scanned surface of the screen is provided by an array of the convex surface portions. In a cross section intersecting the scanned surface, adjacent convex surface portions have different curved shapes. Thus, brightness unevenness of the display image caused by interference of laser beams can be reduced while maintaining a simple structure of the screen such as a microlens array.