A bus bar constitutes a power line and another bus bar constitutes an earth line. The bus bars are layered in the normal direction of an insulating substrate via an insulating member. Here, the bus bar positioned at the upper side is formed by a metal member and the bus bar positioned at the lower side is formed by a wiring layer formed on the insulating substrate. Since one of the bus bars is the wiring layer fixed to the insulating substrate, it is possible to assure heat radiation of the bus bar. Thus, it is possible to make the bus bar a wiring layer having a comparatively small cross sectional area and reduce the semiconductor module size in the normal direction. By mounting the semiconductor module on the drive device for a hybrid vehicle, it is possible to reduce the vertical-direction size when mounted on the vehicle and lower the position of the center of gravity of the vehicle to improve the running stability.