The present application discloses a flexible display device, which solves the problem that a flexible display module has poor bending property in the prior art. The flexible display device provided by the present application comprises a substrate, a supporting film, a buffer layer and a first heat dissipation layer. The supporting film, the buffer layer and the first heat dissipation layer are disposed on a first surface of the substrate in sequence, and a recess is provided on one or more layers of the supporting film, the buffer layer, and the first heat dissipation layer.