A display device has a display screen that displays a real image captured by an image capture device mounted in a construction machine which includes working equipment, and a combined image obtained by overlapping an object image indicating a virtual viewpoint image of an object around the construction machine viewed from a virtual viewpoint of an outside of the construction machine and a construction machine image indicating a virtual viewpoint image of the construction machine viewed from the virtual viewpoint, wherein the display device displays the combined image simultaneously with the real image in a partial region of the real image displayed in the display screen.