A semiconductor device comprises a magneto-resistive device capable of performing multiple functions with low power. The semiconductor device comprises a cell transistor in which a first impurity region and a second impurity region are respectively arranged on both sides of a channel region in a channel direction, a source line connected to the first impurity region of the cell transistor, and the magneto-resistive device connected to the second impurity region of the cell transistor. The first impurity region and the second impurity region are asymmetrical about a center of the cell transistor in the channel direction with respect to at least one of a shape and an impurity concentration distribution.