A semiconductor device includes a plurality of metal patterns formed on a ceramic substrate, and a semiconductor chip mounted on some of the plurality of metal patterns. Also, a plurality of hollow portions are formed in peripheral portions of the plurality of metal patterns. In addition, the plurality of hollow portions are not formed in a region overlapping the semiconductor chip in the plurality of metal patterns. Furthermore, the plurality of hollow portions are provided in a plurality of metal patterns arranged at a position closest to the peripheral portion of the top surface of the ceramic substrate among the plurality of metal patterns.