A technique for activating a fuse function in a semiconductor device in a relatively short time is provided. The semiconductor device includes a second bonding material provided on the upper surface of the insulating substrate, a third bonding material provided on an upper surface of the semiconductor element, a through hole extending from the first circuit pattern to the second circuit pattern via the core material, a conductive film provided on an inner wall of the through hole, and a heat insulating material provided inside the through hole and surrounded by the conductive film in plan view. The conductive film allows the first circuit pattern and the second circuit pattern to be conductive.