The purpose of the present invention is to realize the display device having thin film transistors of the oxide semiconductor of stable characteristics. An example of the concrete structure is that: A display device having a substrate including a display area, plural pixels formed in the display area, the pixel includes a first thin film transistor having an oxide semiconductor film, a first insulating film made of a first silicon oxide on a first side of the oxide semiconductor film, a second insulating film made of a second silicon oxide on a second side of the oxide semiconductor film, wherein oxygen desorption amount per unit area from the first insulating film is larger than that from the second insulating film, when measured by TDS (Thermal Desorption Spectrometry) provided M/z=32 and a measuring range in temperature is from 100 centigrade to 500 centigrade.