To facilitate machining of a hook locking groove of an outer rotating body in a two way torque limiter and miniaturize the device by reducing thickness of the outer rotating body.

The two way torque limiter 27 includes a coil spring 36 installed on an outer circumference part of an inner rotating body 35 with keeping a designated winding and tightening force, a pair of hook parts 36a formed on both end parts of the coil spring 36 and loosening winding and tightening force of the coil spring 36 when the same displace in a direction relatively approaching each other in a side surface view, a hook locking groove 34a arranged on an outer circumference side of the coil spring 36 and having a part thereof cut out, and is provided with the outer rotating body 34 locking a pair of the hook parts 36a at an opposing edge part of the hook locking groove 34a.