A display control drive device sequentially reads display data from a display memory in which the display data is stored, produces three primary color image signals that are applied to pixel locations in a dot-matrix color display device, and transmits the signals through a common external output terminal in a time-sharing manner. The display control drive device produces control signals applied to selection switching elements in the display device and that selectively apply an input image signal to any of three source lines. The display control drive device includes: a unit that determines one horizontal period based on a clock received from outside synchronously with display data; and a signal production circuit that produces and transmits the control signals, applied to the selection switching elements, so that the control signals will have a pulse duration equivalent to a time calculated by trisecting one horizontal period.