PURPOSE: To improve vibration resistance, and to simplify structure by applying thermal conductive fillers onto an integrated circuit element loaded onto a substrate, fast sticking a cooling piece to the thermal conductive fillers and interposing soft adhesives between the cooling piece and a mounting plate for the cooling piece.

CONSTITUTION: Thermal conductive fillers 3 are applied onto an integrated circuit element 2 loaded onto a substrate 1, a cooling piece 4 is fast stuck to the thermal conductive fillers 3, and soft adhesives 6 are interposed between the cooling piece 4 and a mounting plate 5 for the cooling piece 4. A thermal compound, grease, a liquid metal, etc., are used as said thermal conductive fillers 3, and a waterproof sealant, a two-part type metallic compound, solder, etc., are employed as the soft adhesives 6. A refrigerant 9 is flowed in said cooling piece 4, and the top section 10 penetrated into an opening section 51 in the mounting plate 5 and extended to an upper section in the cooling piece 4 is fixed to the mounting plate 5 by curing the soft adhesives 6 interposed between the top section 10 and a flange 7 into which an O ring 8 is interior- finished.