The reliability of an electronic device is improved. An electronic device has a wiring substrate and a housing made of a metal for supporting the wiring substrate. A semiconductor device having a switching power transistor is mounted at the wiring substrate. A ground pattern of a conductive film and a heat radiation pattern of a conductive film are formed at the wiring substrate. The heat radiation pattern is not electrically coupled with any electronic component mounted at the wiring substrate, and is also not electrically coupled with the ground pattern. The ground pattern overlaps the semiconductor device in the thickness direction of the wiring substrate. The heat radiation pattern overlaps the ground pattern in the thickness direction of the wiring substrate, and overlaps a region where the housing and the wiring substrate are in contact with each other.