A foldable display device is described. The foldable display device comprises: a first support member and a second support member, which are separated from each other, a display module disposed on the first support member and the second support member, a hinge coupling one side of the first support member and one side of the second support member, a hinge cover surrounding the hinge and comprising a dust cap on an upper edge thereof, a first back cover disposed under the first support member and comprising a first protrusion at one end thereof, and a second back cover disposed under the second support member and comprising a second protrusion at one end thereof, the dust cap is in contact with the first protrusion and the second protrusion when the display module is folded.