An object of the present disclosure is to provide a virtual image display device, a head-up display system and a vehicle which further improve convenience. The virtual image display device according to the present disclosure includes: a display device which outputs a parallax image forming a left eye virtual image and a right eye virtual image, the parallax image having a plurality of regions whose parallax amounts of the left eye virtual image and the right eye virtual image are different; an optical system which displays a virtual image based on the parallax image; and a controller which changes a partition of the plurality of regions of the parallax image according to a situation.