There is provided a flat panel display device and a method of manufacturing the same. A flexible and transparent material is coated on a supporting substrate to a small thickness so that film substrates are easily formed. Step differences are formed in the film substrates so that a distance between pads of the two film substrates is reduced. Since conductive balls with reduced diameters are used so that the pads may be electrically connected, the distance between pads is reduced so that it is possible to easily miniaturize a high resolution flat panel display device, to prevent electrical connection defect between the pads, and to reduce manufacturing expenses.