The picture mode controller for flat panel and flat panel display device including the same includes an input unit to input a first timing signal indicating transmission sections for pixel data, and a second timing signal indicating a transmission time of each pixel data, a pseudo timing signal generating unit to generate a first pseudo timing signal to be used as the first timing signal, a first selecting unit to selectively output the first timing signal and the first pseudo timing signal to allow one of a video picture mode and a black picture mode to be designated, and a selection control unit to control a selecting operation of the first selecting unit based on whether the first timing signal is input from the input unit and whether a period of the second timing signal changes.