A flexible display apparatus (200, 400), comprising: a flexible substrate including a display area and a bending area outside the display area, the bending area to be bent around a bending axis; an inorganic insulating layer on the flexible substrate; a cutout in the inorganic insulating layer in the bending area; a stress relaxation layer filling the cutout; a wiring part on the stress relaxation layer in the bending area; a planarization layer covering the wiring part and on the stress relaxation layer; and a display on the planarization layer in the display area and electrically connected to the wiring part; wherein the stress relaxation layer extends into the display area, and wherein a pad electrode electrically connected to the wiring part is at an edge of the flexible substrate wherein the flexible display apparatus (200, 400) further comprises in the display area, a thin-film transistor electrically connecting the display to the wiring part, wherein a distance from an upper surface of the planarization layer to the flexible substrate in a region overlapping the thin-film transistor is substantially the same as a distance from the upper surface of the planarization layer to the flexible substrate in a region overlapping the cutout, when the bending area is bent, the pad electrode overlaps the display area at the rear of the display area, the thin-film transistor includes a semiconductor layer, a gate electrode, a source electrode, and a drain electrode, and a pixel electrode is disposed on the planarization layer for each pixel and is connected to the drain electrode of the thin-film transistor through a via hole formed in the planarization layer, the stress relaxation layer in the display area includes an upper surface that is higher than or equal to an upper surface of the source electrode and an upper surface of the drain electrode, the upper surface being the surface furthest from the substrate, and the stress relaxation layer in the bending area directly contacts a lower surface of the wiring part, and the stress relaxation layer in the display area includes an opening, and the source electrode and the drain electrode of the thin-film transistor are in the opening. a flexible substrate including a display area and a bending area outside the display area, the bending area to be bent around a bending axis; an inorganic insulating layer on the flexible substrate; a cutout in the inorganic insulating layer in the bending area; a stress relaxation layer filling the cutout; a wiring part on the stress relaxation layer in the bending area; a planarization layer covering the wiring part and on the stress relaxation layer; and a display on the planarization layer in the display area and electrically connected to the wiring part; wherein the stress relaxation layer extends into the display area, and wherein a pad electrode electrically connected to the wiring part is at an edge of the flexible substrate wherein the flexible display apparatus (200, 400) further comprises in the display area, a thin-film transistor electrically connecting the display to the wiring part, wherein a distance from an upper surface of the planarization layer to the flexible substrate in a region overlapping the thin-film transistor is substantially the same as a distance from the upper surface of the planarization layer to the flexible substrate in a region overlapping the cutout, when the bending area is bent, the pad electrode overlaps the display area at the rear of the display area, the thin-film transistor includes a semiconductor layer, a gate electrode, a source electrode, and a drain electrode, and a pixel electrode is disposed on the planarization layer for each pixel and is connected to the drain electrode of the thin-film transistor through a via hole formed in the planarization layer, the stress relaxation layer in the display area includes an upper surface that is higher than or equal to an upper surface of the source electrode and an upper surface of the drain electrode, the upper surface being the surface furthest from the substrate, and the stress relaxation layer in the bending area directly contacts a lower surface of the wiring part, and the stress relaxation layer in the display area includes an opening, and the source electrode and the drain electrode of the thin-film transistor are in the opening.