A display device includes a first nitride insulating film arranged on a first substrate, a gate electrode arranged along a first direction on the first nitride insulating film, a second nitride insulating film arranged on the gate electrode, a first oxide insulating film arranged on the second nitride insulating film, and an oxide semiconductor layer arranged on the first oxide insulating film, wherein the gate electrode has a first titanium layer, an aluminum layer, and a second titanium layer stacked in order from the first nitride insulating film side, and a thickness of the second titanium layer is greater than a thickness of the first titanium layer.