Provided is a semiconductor device that is resistant to the corrosion of titanium nitride forming an anti-reflection film. The semiconductor device includes: a wiring layer which includes a wiring film made of aluminum or an aluminum alloy and formed on a substrate and a titanium nitride film formed on the wiring film; a protection layer which covers a top surface and a side surface of the wiring layer; and a pad portion which penetrates the protection layer and the titanium nitride film, and which exposes the wiring film, the protection layer including a first silicon nitride film, an oxide film, and a second silicon nitride film which are layered in the stated order from the side of the wiring layer.