A control device controls driving of a motor such that a clutch of a power transmission mechanism is moved to a disconnecting position and thereby a belt reacher device is moved around in a forward direction of a vehicle by a return spring of the belt reacher device, if a change from an open state to a closed state of a door is detected by a door switch. The control device controls driving of the motor such that a webbing is winded and thereby the belt reacher device is moved around to a retracted position in a backward direction of the vehicle, if a determination is made that no occupant seated in a passenger seat is detected by an output of an OFF signal from a buckle switch of the passenger seat and a determination is made that start-up of the vehicle is detected by an output of an ON signal from an ignition switch.