A head-up display device that is to be mounted in a moving vehicle and enables an occupant in the moving vehicle to view a virtual image based on a reflected image of projection light in a projection section. The projection section includes an interlayer film, a first glass plate disposed closer to an outside of the moving vehicle, and a second glass plate disposed closer to an inside of the moving vehicle, the first glass plate and the second glass plate disposed opposite each other with the interlayer film therebetween. The first glass plate and the second glass plate each have a tin surface on which tin is detected and a non-tin surface whose tin concentration is lower than the tin concentration on the tin surface.