A display device, comprising: a flexible substrate; a display unit (A/A) on the flexible substrate and including organic light emitting diodes (OLED); a pad portion at an edge region of the flexible substrate, the pad portion including a plurality of pad electrodes; a chip-on film on the pad portion; and an anisotropic conductive film disposed between the pad portion and the chip-on film and configured to attach the pad portion to the chip-on film; characterized in that the ACF comprises: a first non-conductive layer; a pattern layer on the first non-conductive layer and including a plurality of holes; a plurality of conductive balls in the plurality of holes of the pattern layer; and a second non-conductive layer on the pattern layer and the plurality of conductive balls; wherein the plurality of conductive balls each comprises a conductive layer and an insulating layer surrounding the conductive layer, the insulating layer being arranged to burst and expose the conductive layer when pressure is applied to the anisotropic conductive film, wherein a sum of widths of two holes is less than a width of one pad electrode of a plurality of pad electrodes included in a pad portion on which the anisotropic conductive film is disposed, such that at least two holes are disposed to overlap only one pad electrode and the plurality of conductive balls are disposed corresponding to only the plurality of pad electrodes. a flexible substrate; a display unit (A/A) on the flexible substrate and including organic light emitting diodes (OLED); a pad portion at an edge region of the flexible substrate, the pad portion including a plurality of pad electrodes; a chip-on film on the pad portion; and an anisotropic conductive film disposed between the pad portion and the chip-on film and configured to attach the pad portion to the chip-on film; characterized in that the ACF comprises: a first non-conductive layer; a pattern layer on the first non-conductive layer and including a plurality of holes; a plurality of conductive balls in the plurality of holes of the pattern layer; and a second non-conductive layer on the pattern layer and the plurality of conductive balls; wherein the plurality of conductive balls each comprises a conductive layer and an insulating layer surrounding the conductive layer, the insulating layer being arranged to burst and expose the conductive layer when pressure is applied to the anisotropic conductive film, wherein a sum of widths of two holes is less than a width of one pad electrode of a plurality of pad electrodes included in a pad portion on which the anisotropic conductive film is disposed, such that at least two holes are disposed to overlap only one pad electrode and the plurality of conductive balls are disposed corresponding to only the plurality of pad electrodes. a first non-conductive layer; a pattern layer on the first non-conductive layer and including a plurality of holes; a plurality of conductive balls in the plurality of holes of the pattern layer; and a second non-conductive layer on the pattern layer and the plurality of conductive balls; wherein the plurality of conductive balls each comprises a conductive layer and an insulating layer surrounding the conductive layer, the insulating layer being arranged to burst and expose the conductive layer when pressure is applied to the anisotropic conductive film, wherein a sum of widths of two holes is less than a width of one pad electrode of a plurality of pad electrodes included in a pad portion on which the anisotropic conductive film is disposed, such that at least two holes are disposed to overlap only one pad electrode and the plurality of conductive balls are disposed corresponding to only the plurality of pad electrodes.