A flexible display device according to an example embodiment includes: a substrate; a driver integrated circuit (IC) in a non-display portion of the substrate and configured to supply a driving voltage to a display portion of the substrate; a flexible printed circuit board attached to the non-display portion at an outer side of the driver IC; and a printed circuit board attached to the flexible printed circuit board and configured to transfer the driving voltage to the driver IC, wherein the driver IC comprises a base layer, a plurality of bumps at a bottom surface of the base layer, a first layer at an upper surface of the base layer, and second layers at the first layer to correspond to locations of the plurality of bumps.