1. A flexible display device, comprising:a display module including a first non-bending area and a first bending area adjacent to the first non-bending area; and
a cushion layer disposed on a rear surface of the display module,
wherein the cushion layer has a first cushion layer having a first density in the first non-bending area and a second cushion layer having a second density in the first bending area, and the first density is lower than the second density in an unfolded state prior to bending the first bending area, and
wherein the first cushion layer and the second cushion layer are disposed in a same layer and have a uniform thickness.