A semiconductor device has a substrate having electrode pads, a first semiconductor chip mounted on the substrate with a first adhesion layer interposed therebetween, a second semiconductor chip mounted on the first semiconductor chip with a second adhesion layer interposed therebetween and having electrode pads on the upper surface thereof, wires for bonding the electrode pads of the substrate and the electrode pads of the second semiconductor chip to each other, and a mold resin sealing therein the first and second semiconductor chips and the wires. The peripheral edge portion of the first adhesion layer is protruding outwardly from the first semiconductor chip and the peripheral edge portion of the second semiconductor chip is protruding outwardly beyond the peripheral edge portion of the first semiconductor chip.