A display device separates a size-reduced image into a plurality of sub-areas in such a manner that a sub-area farther away from the light sources becomes wider than a sub-area closer to the light sources; compares, in each of the sub-areas, the luminance values of each pixel in a direction perpendicular to the array direction; and selects a pixel having the greatest luminance value, thereby creating line information. The display device then compares a light distribution that is a synthesis of light radiation patterns of the light sources with a luminance distribution indicated by each line information and then adjusts the emission intensity of each of the light sources.