To provide a penetration rod for detecting the rotational load torque of a screw point, in a penetration test for detecting the rotational load torque by rotationally penetrating the penetration rod comprising a rod and the screw point arranged at the distal end, into the ground, and a penetration testing machine and a penetration testing method using the penetration rod.

The penetration rod has a connecting implement for connecting the rod to the screw point. The connecting implement is of a double pipe structure having an outer pipe to which the screw point is connected, and a bar member to which the rod is connected. These outer pipe and bar member are constituted to be normally engaged in a circumferential direction and integrally rotated, while circumferential engagement is released to rotate only the rod when the rod is pulled up to move the bar member in an axial direction. The penetration testing machine and the penetration testing method using the penetration rod are also provided.