A novel memory device is provided. A first cell array including a plurality of memory cells and a second cell array including a plurality of memory cells are stacked. One of two bit lines of a first bit line pair is electrically connected to A memory cells of the first cell array, and the other of the two bit lines of the first bit line pair is electrically connected to D memory cells of the second cell array. One of two bit lines of a second bit line pair is electrically connected to B memory cells of the first cell array and F memory cells of the second cell array, and the other of the two bit lines of the second bit line pair is electrically connected to C memory cells of the first cell array and E memory cells of the second cell array. The first bit line pairs and the second bit line pairs are alternately provided.