A display control device for displaying data stored in a video memory on a flat display such as an EL or liquid crystal display on the basis of display control signals output from a CRT control device, which comprises a memory means that allows data read and write operations to be executed simultaneously and that has a capacity to store at least one screen of display data for display on the flat display and display control means for alternately executing, in accordance with the display control signals, a first operation in which data corresponding to an upper half of the display screen are retrieved from the data stored in the video memory and sequentially output to an upper region of the display, data corresponding to the upper half of the display screen are sequentially stored in the memory means, and data corresponding to a lower half of the display screen stored in the memory means are sequentially output to a lower region of the display, and a second operation in which data corresponding to the lower half of the display screen are retrieved from the data stored in the video memory and sequentially output to the lower region of the display, data corresponding to the lower half of the display screen are sequentially stored in the memory means, and data corresponding to the upper half of the display screen stored in the memory means are sequentially output to the upper region of the display