The head-up display device (1) includes a light source (22); a condensing lens (23); a lens array (24) diffusing light from the condensing lens (23); a liquid-crystal display unit (10) emitting light from the lens array (24) as display light; and a reflecting member (30) reflecting the display light emitted from the liquid-crystal display unit (10) and projecting the display light on a windshield (103). The lens array (24) has, in an emitting surface (24b), a plurality of lens surfaces (24s) projecting toward the liquid-crystal display unit (10) and having an aspherical sectional shape, and, in the lens surface (24s), the curvature radius of a part (24t) emitting display light to be projected on an upper part (103t) of the windshield (103) is smaller than the curvature radius of a part (24u) emitting display light to be projected on a lower part (103u) of the windshield (103).