Provided is a flexible organic light-emitting display device. The flexible display device includes a flexible substrate having a display area, a non-display area, and a bending area. On the flexible substrate, a first insulation layer is formed in a part of the non-display area. The first insulation layer includes a zigzag pattern. A plurality of wirings are electrically connected to the display area and are extended to traverse the non-display area and the bending area and are disposed on the first insulation layer. On the first insulation layer and the plurality of wirings, a passivation layer is formed. By virtue of a zigzag pattern of the first insulation layer, the frequency of occurrence of cracks in the passivation layer is reduced.