The present invention provides a torque-free robot arm, comprising: a base unit; and a first link in which one end is rotatably connected to the base unit to form a first joint as a rotary shaft horizontal to the ground and the center of gravity is separated from the first joint, wherein the first link includes one end arranged at the first joint, the other end arranged along the longitudinal direction of the first link, and a first counter balancer for compensating the gravity of the first link when the first link is rotated around the first joint.