A head-up display device is improved in performance by a reduction in size and the satisfactory correction of optical aberration. A head-up display device includes an image display surface that displays an image, a reflective optical surface that is disposed at a position facing an predetermined observation position of an observer, and a projection optical system that projects the image displayed on the image display surface to the reflective optical surface disposed at the predetermined observation position and allows the observer to visually recognize the enlarged image as a virtual image. In a case in which an optical path, which extends from a center of the image display surface and reaches a center of an eye box, is referred to as an optical axis, the projection optical system includes a first mirror and a second mirror in this order from the image display surface and Conditional Expression (1) is satisfied.