In a semiconductor device, when a printed circuit board is pressed against a bottom part of a case with an adhesive interposed therebetween, the back surface of the printed circuit board is supported by projections formed on the bottom part. Since the gap between the printed circuit board and the bottom part is maintained to have substantially the same height as the projections, the adhesive pressed by the printed circuit board does not spread excessively. At each edge of the printed circuit board in the long-side direction, the end of the adhesive is aligned with or extends slightly beyond the edge. In the short-side direction, the adhesive extends beyond each edge of the printed circuit board, but does not extend over the front surface of the printed circuit board, internal connection terminals, or the front surface of a ceramic circuit board.