It is an object to obtain a liquid crystal display device in which a contact defect is reduced, increase in contact resistance is suppressed, and an opening ratio is high. The present invention relates to a liquid crystal display device having a substrate; a thin film transistor provided over the substrate, which includes a gate wiring, a gate insulating film, an island-shaped semiconductor film, a source region, and a drain region; a source wiring which is provided over the substrate and is connected to the source region; a drain electrode which is provided over the substrate and is connected to the drain region; an auxiliary capacitor provided over the substrate; a pixel electrode connected to the drain electrode; and a protective film formed so as to cover the thin film transistor and the source wiring, where the protective film has an opening, and the auxiliary capacitor is formed in the area where the opening is formed.