PURPOSE: To enable to adjust the pressure by incorporating a measurement element and a pressure fitting to a jig plate, in a semiconductor unit wherein a semiconductor elements and cooling bodies are stacked alternately and clamped.

CONSTITUTION: The flat type semiconductor element unit 1 is composed by alternately stacking the flat type semiconductor elements 2 and the cooling bodies 3, inserting insulation studs 6 between the upper check plate 4 and the lower check plate, and then clamping them with nuts 7. A leaf spring 9 is interposed between the upper check plate 4 and an insulation plate 8 provided on the cooling body 3 at the uppermost stage, and pressure is applied to each element and cooling body. A pressure device 10 consisting of the jig plate 11, a pressing bolt 14, and the measurement element 12 is provided at the upper ends of the insulation studs 6. After pressing up to a prescribed pressure by using the pressure device 10, the nuts are lightly tightened, and the pressure device is removed, thus completing the assembly.