A flexible display device and a method for manufacturing a flexible display device are provided. A flexible display device includes: a support substrate having a first thickness and including a first material, the support substrate further including first and second main faces opposite to each other, a buffer substrate on the first main face of the support substrate, the buffer substrate having a second thickness smaller than the first thickness, and the buffer substrate including a second material more flexible than the first material, a thin-film transistor array on the buffer substrate, such that the buffer substrate is between the thin-film transistor array and the support substrate, and a sealing substrate fixed above the thin-film transistor array, the thin-film transistor array being between the buffer substrate and the sealing substrate.