Provided is an electric power semiconductor device that includes: a heat transfer plate (4) to which a heat release member (9) is bonded with an insulating layer (8) being interposed therebetween; a printed substrate (3) that is arranged with a predetermined clearance to the heat transfer plate (4), and that has an opening (3a) in the vicinities of an electrode pattern (32) formed on an outer side surface; an electric power semiconductor element (2) that is arranged between the heat transfer plate (4) and the printed substrate (3) and has a back surface thereof bonded to the heat transfer plate(4); and a wiring member (5) that has one end thereof bonded to a first bonding part of a main electric power electrode (21C) formed on a surface of the electric power semiconductor element (2), and has the other end thereof bonded to a second bonding part (32p). The device is configured so that at least a part of the second bonding part (32p) falls in a space that extends in the vertical direction from the main electric power electrode (21C) toward the printed substrate (3), and at the same time, the first bonding part is included in a space that extends in the vertical direction from the opening (3a).