A semiconductor device comprising: a semiconductor module including a high-side semiconductor element connected to a first gate terminal and a first source terminal, and a low-side semiconductor element connected to a second gate terminal and a second source terminal; a first control board located directly above the semiconductor module; a first drive element and a second drive element held by the first control board, the first drive element being connected to the first gate terminal and the first source terminal, and the second drive element being connected to the second gate terminal and the second source terminal; a second control board located above the first control board; a third control board located above the second control board; and a plurality of photocouplers held by the second control board, output signals of the photocouplers being input to the first drive element or the second drive element, wherein characterized in that the semiconductor module includes a positive electrode terminal and a ground terminal provided at one peripheral side of the semiconductor module, and an output terminal provided at another peripheral side opposite to the one peripheral side, the first gate terminal and the first source terminal are located at the side of the semiconductor module provided with the positive electrode terminal and the ground terminal, the second gate terminal and the second source terminal are located at the side of the semiconductor module provided with the output terminal, the first control board is electrically connected to the second control board by a first lead and the second control board is electrically connected to the third control board by a second lead, the output terminal of the first drive element is electrically connected to the first gate terminal and the first source terminal of the high-side semiconductor element, and respectively, the output terminal of the second drive element is electrically connected to the second gate terminal and the second source terminal of the low-side semiconductor element, and the first gate terminal and the first source terminal are connected to a high-side first circuit region of the first control board, the high-side first circuit region being located above the high-side semiconductor element, and the second gate terminal and the second source terminal are connected to a low-side first circuit region of the first control board, the low-side first circuit region being located above the low-side semiconductor element. a semiconductor module including a high-side semiconductor element connected to a first gate terminal and a first source terminal, and a low-side semiconductor element connected to a second gate terminal and a second source terminal; a high-side semiconductor element connected to a first gate terminal and a first source terminal, and a low-side semiconductor element connected to a second gate terminal and a second source terminal; a first control board located directly above the semiconductor module; a first drive element and a second drive element held by the first control board, the first drive element being connected to the first gate terminal and the first source terminal, and the second drive element being connected to the second gate terminal and the second source terminal; a second control board located above the first control board; a third control board located above the second control board; and a plurality of photocouplers held by the second control board, output signals of the photocouplers being input to the first drive element or the second drive element, wherein the semiconductor module includes a positive electrode terminal and a ground terminal provided at one peripheral side of the semiconductor module, and an output terminal provided at another peripheral side opposite to the one peripheral side, a positive electrode terminal and a ground terminal provided at one peripheral side of the semiconductor module, and an output terminal provided at another peripheral side opposite to the one peripheral side, the first gate terminal and the first source terminal are located at the side of the semiconductor module provided with the positive electrode terminal and the ground terminal, the second gate terminal and the second source terminal are located at the side of the semiconductor module provided with the output terminal, the first control board is electrically connected to the second control board by a first lead and the second control board is electrically connected to the third control board by a second lead, the output terminal of the first drive element is electrically connected to the first gate terminal and the first source terminal of the high-side semiconductor element, and respectively, the output terminal of the second drive element is electrically connected to the second gate terminal and the second source terminal of the low-side semiconductor element, and the first gate terminal and the first source terminal are connected to a high-side first circuit region of the first control board, the high-side first circuit region being located above the high-side semiconductor element, and the second gate terminal and the second source terminal are connected to a low-side first circuit region of the first control board, the low-side first circuit region being located above the low-side semiconductor element.