A display device includes: a display screen displaying screen images; a required-brightness computation unit computing required brightnesses for each of the screen images; a brightness determination unit comparing the required brightnesses computed for each of the screen images, and determining the screen image corresponding to the required brightness having highest brightness to be a maximum-required-brightness image; and a brightness control unit performing light-source brightness control and performing image gradation control, the light-source brightness control controlling the brightness of the light source so as to make the brightness of the light source the set brightness for the maximum-required-brightness image, the image gradation control controlling a gradation of the image displayed on the liquid-crystal panel in accordance with the brightness of the light source, so as to make a brightness of each of the screen images other than the maximum-required-brightness image the set brightness specified for each of the screen images.