A semiconductor device having a novel structure is provided in which a transistor including an oxide semiconductor and a transistor including a semiconductor material which is not an oxide semiconductor are stacked. Further, a semiconductor device in which a semiconductor element and a capacitor are formed efficiently is provided. In a semiconductor device, a first semiconductor element layer including a transistor formed using a semiconductor material which is not an oxide semiconductor, such as silicon, and a second semiconductor element layer including a transistor formed using an oxide semiconductor are stacked. A capacitor is formed using a wiring layer, or a conductive film or an insulating film which is in the same layer as a conductive film or an insulating film of the second semiconductor element layer.