The present disclosure relates to a flexible display device, including a flexible substrate. The substrate includes a first portion, a second portion and a bending portion connecting the first portion to the second portion, wherein the flexible substrate has a thickness T. A plurality of display pixels is located at a side of the first portion of the flexible substrate. A supporting layer is located at a side of the flexible substrate facing away from the plurality of display pixels and includes a first supporting layer corresponding to the first portion and a second supporting area corresponding to the second portion. A thickness of the first supporting layer is T1, a thickness of the second supporting layer is T2, and a width of the bending portion is W, wherein W ≥ ( 2 ⁢ T + T ⁢ ⁢ 1 + T ⁢ ⁢ 2 ) ⁢ π 2 . Therefore, a narrow border is achieved, and the problem of interference during bending is alleviated.