Abstract: A device to draw the bow string of a crossbow is disclosed, comprising a housing and an elongate arm both extendable from and rectilinearly moveable with respect to the housing in at least one direction coaxial with the longitudinal axis of the arm. A drive mechanism is provided in mechanical communication with the arm, such that operation of the drive mechanism effects rectilinear movement of the arm in the at least one direction with respect to the housing. The arm is further provided with a fork for engaging the crossbow bow string. For crossbows of the type including a longitudinal barrel having a recessed track therein, an aligning pin is provided, the aligning pin slidingly receivable within the crossbow track such that the path of travel of the arm is substantially parallel to the longitudinal axis of the track.