A semiconductor device includes a first signal line, a second signal line, a memory cell, and a potential converter circuit. The memory cell includes a first transistor including a first gate electrode, a first source electrode, a first drain electrode, and a first channel formation region; a second transistor including a second gate electrode, a second source electrode, a second drain electrode, and a second channel formation region; and a capacitor. The first channel formation region and the second channel formation region include different semiconductor materials. The second drain electrode, one electrode of the capacitor, and the first gate electrode are electrically connected to one another. The second gate electrode is electrically connected to the potential converter circuit through the second signal line.