Provided is a head-up display device such that shaking of a display image due to vibration can be mitigated. This head-up display device, which reflects display light output from a display unit with a reflection unit so as to produce an image to be viewed, includes a first supporting part for supporting the reflection unit rotatably about a rotation axis and a first supported part provided at one end of the reflection unit and supported by the first supporting part. The first supported part has a spherical surface formed thereon, and the first supporting part has a sliding surface that is formed therein and is in substantially point contact or line contact with the spherical surface formed on the first supported part. A first elastic member that presses the first supported part and the first supporting part against each other in the rotation axis direction is provided.