An improvement is achieved in the heat dissipation property of an electronic device including power transistors. A semiconductor module includes first and second packages included in an inverter circuit. In the first package, a semiconductor chip having a high-side power transistor is embedded. In the second package, a semiconductor chip having a low-side power transistor is embedded. At the both wide surfaces of the first and second packages, first metal electrodes electrically coupled to respective collector electrodes of the power transistors and second metal electrodes electrically coupled to respective emitter electrodes of the power transistors are exposed. To the first and second metal electrodes of the first and second packages, four respective bus bar plates having areas larger than those of the first and second metal electrodes are joined.