To solve a problem as follows: at the time of bonding an insulating substrate with a semiconductor chip mounted to a heat radiating plate with a case or the like fixed to the heat radiating plate, a low heat resistant component such as the case or the like of the peripheral member deforms by the heat to cause a malfution.

The insulating substrate 33 with the semiconductor chip 31 mounted thereon is soldered to the heat radiating plate 11 through steps of: decompressing an atmosphere in a decompression vessel 15 with a laminated body inserting the solder 34a between the members (the insulating substrate 33 and the heat radiating plate 11) to be bonded provided; heating the solder 34a up to the soldering-capable bonding temperature; pressurizing the atmosphere in the decompression vessel 15 up to the pressure higher than the decompressed atmosphere decompressed in the decompression process with the bonding temperature of the solder 34a after the heating up process held; and holding the heating process of the bonded temperature of the solder 34a until the completion of the bonding between the member to be bonded and the solder 34a after the temperature eleveting process.