A flexible display device includes a flexible display panel and a chip on film (COF) bonded to the flexible display panel; wherein the flexible display panel is divided into a display region, a bonding region on a side of the display region, and a bending region between the display region and the bonding region; wherein the COF comprises a main body portion and two expansion bonding portions respectively disposed at two ends of one side of the main body portion; wherein an edge of the main body portion adjacent to the two expansion bonding portions are disposed with a plurality of connection pins; wherein the COF is bonded to the bonding region of the flexible display panel through the plurality of connection pins.