Provided is a semiconductor device including: a first transistor over a substrate, the first transistor having a gate electrode, an oxide semiconductor film, and a gate insulating film between the gate electrode and the oxide semiconductor film; an insulating film over the first transistor, the insulating film having a first film and a second film over the first film; and a terminal electrically connected to the oxide semiconductor film through an opening portion in the insulating film. The insulating film has a first region in contact with the terminal, and the first region has an oxygen composition larger than that in another region of the insulating film.