A semiconductor device comprising: a first electrical conductor comprising a first joint surface and a first bottom surface perpendicular to the first joint surface; a second electrical conductor comprising a second joint surface opposite the first joint surface and a second bottom surface perpendicular to the second joint surface and flush with the first bottom surface; a plate-shaped first semiconductor element which is a power semiconductor element and which is disposed between the first and second electrical conductors, one electrode of which is joined to the first joint surface of the first electrical conductor, and another electrode of which is connected to the second joint surface of the second electrical conductor; a plate-shaped second semiconductor element which is a diode and which is disposed between the first and second electrical conductors, one electrode of which is joined to the first joint surface of the first electrical conductor, and the other electrode of which is connected to the second joint surface of the second electrical conductor; a first power terminal comprising a proximal end portion joined to the first joint surface and extending outwardly from the first electrical conductor; a second power terminal extending outwardly relative to the second electrical conductor from the second joint surface; a signal terminal connected to the first semiconductor element; and a insulator which covers the proximal end portion of the first power terminal, a proximal end portion of the second power terminal, a proximal end portion of the signal terminal, and the first and second electrical conductors, the insulator comprising a flat bottom surface which extends perpendicular to the first and second semiconductor elements and in which the first bottom surface of the first electrical conductor and the second bottom surface of the second electrical conductor are exposed, a flat first lateral surface extending perpendicular to the bottom surface, a second lateral surface extending perpendicular to the bottom surface and opposed parallel to the first lateral surface, a ceiling surface located between the first and second lateral surfaces and opposed to the bottom surface, a first end surface extending across the bottom surface and respective one ends of the first and second lateral surfaces, and a second end surface extending across the bottom surface and the respective other ends of the first and second lateral surfaces, the first power terminal, the second power terminal, and the signal terminal extending outwardly from the first end surface, the second end surface, and the ceiling surface, respectively, the first end surface, the ceiling surface, and the second end surface of the insulator being formed with a parting line. a first electrical conductor comprising a first joint surface and a first bottom surface perpendicular to the first joint surface; a second electrical conductor comprising a second joint surface opposite the first joint surface and a second bottom surface perpendicular to the second joint surface and flush with the first bottom surface; a plate-shaped first semiconductor element which is a power semiconductor element and which is disposed between the first and second electrical conductors, one electrode of which is joined to the first joint surface of the first electrical conductor, and another electrode of which is connected to the second joint surface of the second electrical conductor; a plate-shaped second semiconductor element which is a diode and which is disposed between the first and second electrical conductors, one electrode of which is joined to the first joint surface of the first electrical conductor, and the other electrode of which is connected to the second joint surface of the second electrical conductor; a first power terminal comprising a proximal end portion joined to the first joint surface and extending outwardly from the first electrical conductor; a second power terminal extending outwardly relative to the second electrical conductor from the second joint surface; a signal terminal connected to the first semiconductor element; and a insulator which covers the proximal end portion of the first power terminal, a proximal end portion of the second power terminal, a proximal end portion of the signal terminal, and the first and second electrical conductors, the insulator comprising a flat bottom surface which extends perpendicular to the first and second semiconductor elements and in which the first bottom surface of the first electrical conductor and the second bottom surface of the second electrical conductor are exposed, a flat first lateral surface extending perpendicular to the bottom surface, a second lateral surface extending perpendicular to the bottom surface and opposed parallel to the first lateral surface, a ceiling surface located between the first and second lateral surfaces and opposed to the bottom surface, a first end surface extending across the bottom surface and respective one ends of the first and second lateral surfaces, and a second end surface extending across the bottom surface and the respective other ends of the first and second lateral surfaces, the first power terminal, the second power terminal, and the signal terminal extending outwardly from the first end surface, the second end surface, and the ceiling surface, respectively, the first end surface, the ceiling surface, and the second end surface of the insulator being formed with a parting line.