A semiconductor device comprising: a first semiconductor element; a second semiconductor element; a first plate-like part that is made of an electric conductor, is electrically connected to an top-face-side electrode of the first semiconductor element, and includes a first joint part that projects from a side face of the first plate-like part; a second plate-like part that is made of an electric conductor, and includes a second joint part that projects from a side face of the second plate-like part; a third-plate-like part that is made of an electric conductor, is electrically connected to an top-face-side electrode of the second semiconductor element, and includes a third joint part that projects from a side face of the third plate-like part; and a fourth plate-like part that is made of an electric conductor, and includes a fourth joint part that projects from a side face of the fourth plate-like part, wherein a bottom face of the first joint part and a top face of the second joint part face one another, and are electrically connected via an electro-conductive bonding material, and a bonding-material-thickness ensuring means is provided in a zone where the bottom face of the first joint part and the top face of the second joint part face one another to ensure a thickness of the electro-conductive bonding material between an upper portion of a front end of the second joint part and the bottom face of the first joint part, characterized in that the bonding-material-thickness ensuring means is a groove formed from the bottom face of the first joint part, wherein the groove has a semi-circular or semi-elliptical sectional shape, and the upper portion of the front end of the second joint part is fixed via the bonding material at a position overlapping with the groove in plan view. a first semiconductor element; a second semiconductor element; a first plate-like part that is made of an electric conductor, is electrically connected to an top-face-side electrode of the first semiconductor element, and includes a first joint part that projects from a side face of the first plate-like part; a second plate-like part that is made of an electric conductor, and includes a second joint part that projects from a side face of the second plate-like part; a third-plate-like part that is made of an electric conductor, is electrically connected to an top-face-side electrode of the second semiconductor element, and includes a third joint part that projects from a side face of the third plate-like part; and a fourth plate-like part that is made of an electric conductor, and includes a fourth joint part that projects from a side face of the fourth plate-like part, wherein a bottom face of the first joint part and a top face of the second joint part face one another, and are electrically connected via an electro-conductive bonding material, and a bonding-material-thickness ensuring means is provided in a zone where the bottom face of the first joint part and the top face of the second joint part face one another to ensure a thickness of the electro-conductive bonding material between an upper portion of a front end of the second joint part and the bottom face of the first joint part, characterized in that the bonding-material-thickness ensuring means is a groove formed from the bottom face of the first joint part, wherein the groove has a semi-circular or semi-elliptical sectional shape, and the upper portion of the front end of the second joint part is fixed via the bonding material at a position overlapping with the groove in plan view.