In a semiconductor device, a substrate has a main surface. A first semiconductor chip has a first front surface and a first back surface, and is mounted on the main surface via a plurality of bump electrodes. A first spacer has a second front surface and a second back surface that is mounted on the main surface. A height of the second front surface from the main surface is within a range between a highest height and a lowest height of the first back surface from the main surface. A second spacer has a third front surface and a third back surface that is mounted on the main surface. A height of the third front surface from the main surface is within the range between the highest height and the lowest height of the first back surface from the main surface.