A bus bar has a lead portion and a bus bar portion which are integrally shaped. The lead portion is provided in such a shape that branches from the bus bar portion. A part of the lead portion forms a connection part directly electrically connected with a transistor electrode and a diode electrode by a connecting material such as solder. The thickness of the lead portion including the connection part is made smaller than the thickness of the bus bar portion. Accordingly, such an interconnection structure can be provided in which the electrode of the semiconductor device and the bus bar are electrically directly connected with each other and thermal stress at the connection part therebetween can be relieved.