A semiconductor device including a main board; a first board provided on the main board; first and second semiconductor elements provided on the first board; a first positive terminal provided on the first board; a first negative terminal provided on the first board; a first output terminal provided on the first board; a second board provided on the main board; third and fourth semiconductor elements provided on the second board; a second positive terminal provided on the second board; a second negative terminal provided on the second board; a second output terminal provided on the second board; a first terminal plate connecting the first positive terminal and the second positive terminal, a second terminal plate connecting the first negative terminal and the second negative terminal, and a third terminal plate connecting the first output terminal and the second output terminal.