In a semiconductor memory device, one electrode of a capacitor is connected to a bit line, and the other electrode of the capacitor is connected to a drain of a cell transistor. A source of the cell transistor is connected to a source line. When a stack capacitor, for example, is used in this structure, one electrode of the capacitor is used as part of the bit line. An impurity region formed on the semiconductor substrate or a wiring parallel to a word line can be used as the source line; thus, the structure of a DRAM is simplified.