To provide a technique displaying a display object in a manner superimposed on a background so as to attract attention of a driver.

For controlling an in-vehicle display unit displaying a display object in a manner superimposed on a background, when a first background color as the color of a background when a vehicle travels along a first section is different from the second background color as the color a background when the vehicle travels along a second section following the first section, a color that is different from the second background color and different from at least one of a first display color as the color of the display object and the first background color when the vehicle travels along the first section, is set as a second display color that is the color of the display object when the vehicle travels along the second section. The in-vehicle display unit is controlled so that the display object is displayed in the second display color when the vehicle travels along the second section.