A semiconductor device includes a plurality of first conductive lines, a second conductive line, a third conductive line, a first semiconductor layer and a memory layer. The first conductive lines and the second conductive line between the first conductive lines are stacked along a first direction. The third conductive line extends along the first direction. The first semiconductor layer extends along the first direction to surround the third conductive line. The memory layer is disposed between the first conductive lines in the first direction, and the memory layer is disposed between the first semiconductor layer and the second conductive line in a second direction different from the first direction.