First switches include first electrodes, which are mutually connected with each other via a first internal bus bar, and second electrodes, which are mutually connected with each other via a second internal bus bar. A first resin member encapsulates the first switches and the first and second internal bus bars. Second switches include third electrodes, which are mutually connected with each other via a third internal bus bar, and fourth electrodes, which are mutually connected with each other via a fourth internal bus bar. A second resin member that encapsulates the second switches and the third and fourth internal bus bars. The second module is arranged alongside with the first module. The second internal bus bar and the third internal bus bar are partially exposed from the first resin member and the second resin member, respectively, and are directly joined with each other.