A foldable display device that reduces a transfer or distortion phenomenon of a folding part, prevents a display panel from sagging, and exhibits excellent folding characteristics. The foldable display device includes a display panel including a folding part and a non-folding part, a plurality of middle frames disposed at the lower surface of the display panel, and a bottom case for receiving the display panel and the middle frames. Each of the middle frames includes a frame folding part located at a region corresponding to the folding part of the display panel and a plurality of plates located at a region corresponding to the non-folding part of the display panel.