To provide a head up display device which has a constitution capable of adjusting an image location of a display image according to a visual line position of a user, and can perform position adjustment of appropriate display image.

The head up display device is equipped with an eyeball position detecting means for detecting the eyeball position of the user, a control means 9 for calculating the image location of the display image V based on a first eyeball position detected by the eyeball position detecting means, an optical path adjusting means 4a for adjusting the outgoing direction of a visible light L based on the calculation result of the control means 9, and a storage means 9a for storing the first eyeball position as the reference eyeball position. When it is determined that a second eyeball position detected by the eyeball position detecting means has a difference of not less than a predetermined distance or a predetermined angle to the reference eyeball position after the time when the first eyeball position is detected, the control means 9 calculates the image location of the display image V based on the second eyeball position, and drives the optical path adjusting means 4a based on the calculation result.