To stabilize a generated torque for a long period by limiting a rise of inside temperature in the torque limiter of a frictional system.

This limiter comprises an inner member 1, an outer member 3 fitted on its inner member, a coil spring 2 having a hook 6 in the axial direction fitted with the required tightening power on the external diameter face of the above inner member and a cover 4 fitted to the outer member 3 between the above inner member 1 and the outer member 3. In the torque limiter that a part of the above coil spring 2 is fitted to the above outer member 3 and a regular torque is produced by the friction between the coil sprint 2 and the inner member 1, the radiation fin 18 is provided with the inner member 1 and/or the outer member 3.