A vehicle-use display device comprising: a road slope information acquisition unit configured to acquire slope information of a road on which an own car is traveling; a vehicle speed acquisition unit configured to acquire a vehicle speed of the own car; an other-car detection unit configured to detect a car preceding the own car and a car following the own car; an image pickup unit comprising a camera and an image pickup control unit and being configured to take an image of view to rear of the own car; a display unit; and a display control unit configured to display a rearward image taken by the image pickup unit in the display unit; characterized in that the display control unit is configured to selectively perform a rearward normal display mode and a rearward enlarged display mode, the rearward normal display mode being a mode in which an image of a first area in the rearward image is displayed in the display unit, the rearward enlarged display mode being a mode in which an image of a second area in the rearward image smaller than the first area is displayed in the displayed unit in an enlarged manner, and the display control unit is configured to perform the rearward enlarged display mode if: it is detected that an upward slope of the road on which the own car is traveling has increased based on the slope information acquired by the road slope information acquisition unit; it is detected that the vehicle speed of the own car has decreased after the upward slope of the road has increased based on the vehicle speed acquired by the vehicle speed acquisition unit; there is no preceding car that is closely lined up with the own car based on a result of detection by the other-car detection unit; and there is the following car that is not closely lined up with the own car. a road slope information acquisition unit configured to acquire slope information of a road on which an own car is traveling; a vehicle speed acquisition unit configured to acquire a vehicle speed of the own car; an other-car detection unit configured to detect a car preceding the own car and a car following the own car; an image pickup unit comprising a camera and an image pickup control unit and being configured to take an image of view to rear of the own car; a display unit; and a display control unit configured to display a rearward image taken by the image pickup unit in the display unit; characterized in that the display control unit is configured to selectively perform a rearward normal display mode and a rearward enlarged display mode, the rearward normal display mode being a mode in which an image of a first area in the rearward image is displayed in the display unit, the rearward enlarged display mode being a mode in which an image of a second area in the rearward image smaller than the first area is displayed in the displayed unit in an enlarged manner, and the display control unit is configured to perform the rearward enlarged display mode if: it is detected that an upward slope of the road on which the own car is traveling has increased based on the slope information acquired by the road slope information acquisition unit; it is detected that the vehicle speed of the own car has decreased after the upward slope of the road has increased based on the vehicle speed acquired by the vehicle speed acquisition unit; there is no preceding car that is closely lined up with the own car based on a result of detection by the other-car detection unit; and there is the following car that is not closely lined up with the own car. it is detected that an upward slope of the road on which the own car is traveling has increased based on the slope information acquired by the road slope information acquisition unit; it is detected that the vehicle speed of the own car has decreased after the upward slope of the road has increased based on the vehicle speed acquired by the vehicle speed acquisition unit; there is no preceding car that is closely lined up with the own car based on a result of detection by the other-car detection unit; and there is the following car that is not closely lined up with the own car.