A stud bolt has a first thread portion, a second thread portion, an engagement portion and a large diameter portion. The first thread portion is screwable into a first member about a screw axis. The second thread portion is screwable into a second member about the screw axis and is provided coaxially with the first thread portion. The engagement portion is provided on a side of the second thread portion, which is opposite from the first thread portion. The large diameter portion has a circular cross-section perpendicular to the screw axis. The large diameter portion is located between the first thread portion and the second thread portion. An outer diameter of the large diameter portion is larger than an outer diameter of the first thread portion and the outer diameter of the second thread portion.