Reduction in reliability of a semiconductor device is suppressed. A semiconductor device includes a plurality of metal patterns formed on a ceramic substrate, and a plurality of semiconductor chips mounted on the plurality of metal patterns. Also, the plurality of metal patterns include metal patterns MPH and MPU which face each other. In addition, a region which is provided between these metal patterns MPH and MPU and which is exposed from the plurality of metal patterns extends so as to zigzag along an extending direction of the metal pattern MPH.