Embodiments of this disclosure provide a flexible display device. The flexible display device comprises a flexible display panel and a folding mechanism. The folding mechanism comprises a first cabinet and a second cabinet overlapping each other, and a guiding mechanism. The second cabinet can move straight relative to the first cabinet through the guiding mechanism. The flexible display device further comprises a guiding portion and an adjusting lever in the second cabinet. The guiding portion is at a push-pull end of the second cabinet. The adjusting lever can move between the push-pull end and an end opposite to the push-pull end. One end of the flexible display panel is fixed to the push-pull end of the first cabinet, and the other end is fixed to the adjusting lever in an opposite direction. A locking mechanism fixes relative positions of the first cabinet, the second cabinet and the adjusting lever.