According to one embodiment, a display device includes a display panel in which pixel units are arranged, and a controller configured to generate image signals by multiplying display data externally supplied to each line by a luminosity adjustment factor, to supply the generated image signals to the pixel units, to accumulate power consumption of each line, and to execute black insertion if the accumulated power consumption is determined to be greater than power consumption of one previous display frame by a predetermined value, wherein the luminosity adjustment factor is acquired by substituting the power consumption of one previous frame to a decreasing function, and a display pattern including a plurality of continuing black display lines is synchronized with supply of the image signals and is displayed moving the same direction of a screen scanning direction of the display panel during the black insertion.