A shared base plate includes a plurality of base portions to which a plurality of electronic components including semiconductor switching elements are to be mounted, and a terminal formed portion formed so as to extend from the base portion to the outer side. The terminal formed portion includes a discrimination terminal which is used as a terminal in one of a first semiconductor module and a second semiconductor module and which is not used as a terminal in the other one. If the discrimination terminal that is not used as a terminal is cut to be short, it becomes possible to easily discriminate the semiconductor module from another semiconductor module having the shared base plate by outer appearances.