A flat panel display device is disclosed that may include a light-emitting layer portion including a first electrode, a second electrode, and an organic light-emitting layer between the first and second electrodes; at least two thin film transistors for controlling the light-emitting layer portion; a scanning signal line for supplying a scanning signal to the thin film transistor; a data signal line for supplying a data signal to the thin film transistor; a light emitting region having a common power supply line for supplying current to the light-emitting layer portion; and a peripheral common power supply line having at least one curved portion and connected to the common power supply line on a panel of a non-light emitting region except the light emitting region, wherein the common power supply line has a reduced wiring width while maintaining a constant wiring resistance to thereby reduce the total size of the display panel.