According to one embodiment, a semiconductor device includes, an oxide semiconductor layer including a channel region, and a source region and a drain region, a first insulation film covering the channel region and exposing the source region and the drain region, a first conductive layer including a gate electrode, and a first terminal electrode, a second insulation film covering the first conductive layer, the source region and the drain region, a second conductive layer including a source electrode, a drain electrode, and a second terminal electrode which is opposed to the first terminal electrode via the second insulation film, and a third insulation film interposed between the second insulation film, and the source electrode and the drain electrode.