Disclosed is a seat belt forwarding system having a rotary arm carrying an end of a seat belt at its free end. The rotary arm is driven by a tension cable by way of a rotary unit having three transmitting members which are coaxially arranged and supported in a freely rotatable manner. By advantageous arrangement of the transmitting members, even when motion of the rotary arm is obstructed, spring means advantageously absorb the resultant force and no excessive force will be produced in the rotary unit. The first spring means biases the second transmitting member in a rearward direction while the second spring means is engaged between the second and the third transmitting members. The transmitting of force between the transmitting members is achieved by projections provided in the opposing surfaces of the transmitting members, in addition to the transmission of force between the second and the third transmitting members by the second spring means.
