PURPOSE: To suppress a rise in the temperature of an IC and to contrive a reduction in irregularity in the temperature rise of the IC by a method wherein an electronic component is fixed on a heat dissipation member via a rubber and thereafter, the rubber is softened and expanded under a high-temperature state and air layers between the component and the rubber and between the rubber and the member are removed.

CONSTITUTION: An IC 3 is first put on a thermal bus 2 via a rubber 4 and after the bus is soldered on a substrate 1, they are left to stand in a high- temperature state, the rubber 4 is softened and expanded to remove air layers between the IC 3 and the rubber 4 and between the rubber 4 and the bus 2. After the rubber is made to soak in the air layers, they are left to stand it normal temperatures and the IC 3 and the rubber 4 and the rubber 4 and the bus 2 are mutually made to completely adhere. Thereby, heat which is generated in the IC 3 is absorbed in a beat dissipation part 21 via the base of the IC 3, the rubber 4 and the bus 2 and the IC is cooled. Accordingly, as no air layer is interposed between the IC and the rubber and between the rubber and the bus, the heat dissipation of the IC is stabilized and irregularity in a rise in the temperature of the IC is eliminated.