To provide a semiconductor device that is suitable for miniaturization. The semiconductor device includes a first transistor, a second transistor over the first transistor, a barrier layer between the first transistor and the second transistor, a first electrode between the first transistor and the barrier layer, and a second electrode between the hairier layer and the second transistor and overlapping the first electrode with the barrier layer therebetween. A gate electrode of the first transistor, the first electrode, one of a source electrode and a drain electrode of the second transistor are electrically connected to one another. A channel is formed in a first semiconductor layer including a single crystal semiconductor in the first transistor. A channel is formed in a second semiconductor layer including an oxide semiconductor in the second transistor.