The present invention provides a rollable flexible display device. The flexible display module of the present invention is covered with strip structures. Material of the strip structures is flexible silicone material, and the strip structure are embedded with universal ball assemblies having a very low sliding resistance, and a special reel mechanism is also used, and distal ends of the reel are disposed with universal ball assemblies. The conventional spiral spring mechanism is replaced, sliding is replaced by rolling to reduce contact friction. Therefore, phenomenon of jammed situation and un-smooth motion is mitigated.