Head-Up Display Apparatus

A head-up display apparatus includes: a projection optical system that projects a virtual image; an environment monitor portion as an object detection part that detects an object present in a detection region and detects a distance from the projection optical system to the object as a target distance; an arrangement change apparatus as a projection distance change part that periodically changes a projection distance of a virtual image from the projection optical system ; and a main control apparatus and a display control portion as an image addition part that adds a related-information image as a virtual image by the projection optical system to the detected object at timing when the target distance substantially matches the projection distance.