Conventionally, the layer of the insulator between a cathode and an anode is formed by a droplet discharge method, vapor deposition, or the like separately from an interlayer insulating film formed over a thin film transistor, which creates problems of increase in cost and the number of manufacturing steps. A memory device of the present invention includes a first conductive film; an insulating film formed over the first conductive film; and a second conductive film formed over the insulating film, and an opening and a contact hole which are formed in the insulating film. Further, the insulating film exists between the first conductive film and the second conductive film formed in the opening, and the first conductive film and the second conductive film are electrically connected in the contact hole.