A flexible display device is provided. The display device includes an outer frame, a first supporting plate, a second supporting plate, a roller device, rotating shaft assemblies, and a transmission assembly. When the second supporting plate and the first supporting plate are expanded relatively or merged with each other, the transmission assembly guides the roller device and the rotating shaft assemblies to rotate simultaneously, ensuring smooth transmission of screens in a stretching process or a contracting process, and improving service life of a flexible display screen.