To provide a shaft-shaped fastening tool capable of surely controlling fastening torque while visually confirming it, and being inexpensively manufactured.

Male screw parts 3, 4 and a pin tail 5 are mounted on a round shaft body 2, and a rupture groove 6 ruptured by the action of specific fastening torque is formed on a basic end of the pin tail 5. As a material of the shaft body 2, a steel material free from heat treatment for improving bearing force, is applied.