Visually soldering is easy, and the solder reflow process in a state in which the external terminals are attached to the case to provide a semiconductor module capable. The semiconductor module includes a rectangular base plate, a substrate formed with a circuit including a semiconductor chip or the like on the base plate, attached to said base plate, and a rectangular parallelepiped shape of the resin case for accommodating the substrate therein includes a plurality of external terminals lower end fixed to the substrate an upper end so as to expose the upper surface of the case, the. First case opening cut out the front and back of the case along the longitudinal direction from the upper side and the second casing opening is provided, between the first casing opening and the second casing opening wherein the case upper surface, and an external terminal holding portion for holding the longitudinal direction to expose the upper end of the plurality of external terminals. The first case opening portion and the second sealing material on the substrate upper surface from the case opening is injected semiconductor module is sealed.