The purpose of the invention is to form a flexible display device where the substrate is made of resin, wherein the TFT can be annealed in high temperature; consequently, a reliability of the TFT is improved. The concrete measure is as follows. A display device having a pixel electrode and a TFT including a semiconductor layer on a substrate comprising: a source region of the semiconductor layer connects with a source electrode, a drain region of the semiconductor layer connects with a drain electrode; the pixel electrode connects with the source electrode; the drain electrode connects with a video signal line; a distance between the drain electrode and the substrate is smaller than a distance between the semiconductor and the substrate, the semiconductor layer is formed between the pixel electrode and the substrate.