In a memory cell area of a semiconductor device, first, second, and third inter-layer insulating films respectively cover a cell transistor, a bit wiring line, and a capacitor which are connected to each other. In an adjacent peripheral circuit area, a peripheral-circuit transistor is covered with the first inter-layer insulating film, a first-layer wiring line connected to the peripheral-circuit transistor is provided on the first inter-layer insulating film and covered with the second inter-layer insulating film, and a second-layer wiring line is provided on the third inter-layer insulating film. In the memory cell area, a landing pad is provided on the second inter-layer insulating film and between the capacitor and a contact plug for connecting the capacitor to the cell transistor. An assist wiring line connected to the first-layer wiring line is provided on the main surface of the second inter-layer insulating film, on which the landing pad is provided.