A semiconductor module includes semiconductor elements, a case that houses the semiconductor elements, an external terminal electrically connecting the semiconductor elements and an external conductor, and a nut into which a bolt that secures the external conductor and the external terminal is threaded. The nut includes a cylindrical main body having a threaded hole, and a flange projecting in a direction radially outward of a center axis of the threaded nut hole and being disposed on one face of the main body. The case includes a wall surrounding the nut, the wall having a first recess that houses the main body, a second recess above the first recess and housing the flange, and a notch cut in a portion of the wall surrounding the main body. The first recess extends deeper than the main body, and the fillet is formed on a floor surface of the first recess.