An electronic control unit is equipped with a semiconductor module having a semiconductor chip electrically connected to the first circuit pattern and the second circuit pattern. A resin body is wrapped around the semiconductor chip. A first metal plate has a side connected to the semiconductor chip and an other side connected to the first circuit pattern. A radiator projects toward and is connected to the first circuit pattern by a first heat conductor. As a result, heat generated by the semiconductor chip is transmitted to the radiator through the first metal plate, the first circuit pattern, and the first heat conductor during operation of the semiconductor module.