A foldable display device, and more particularly, a foldable display device includes a flexible display panel; a support member disposed below the flexible display panel; and a cover member disposed on the flexible display panel, in which the cover member includes a glass disposed on the flexible display panel; a first adhesive layer disposed on the glass; and a barrier film disposed on the first adhesive layer, and a thickness of the barrier film is 30 μm to 70 μm, a thickness of the first adhesive layer is 5 μm to 10 μm, and a modulus of the first adhesive layer is 5×104 Pa to 5×108 Pa.