A device for delivering a conveying truck into a screw driving area has a truck delivery screw and a truck propulsion screw which are connected in tandem via a single position electromagnetic clutch and both the screws are configured to rotate in the same phase in the transmission state of the electromagnetic clutch. Two front and back driven rollers are pivotally connected to a conveying truck at an interval at which the driven rollers can engage both screws. A truck delivery mechanism is provided for delivering the conveying truck in the disengaged state of the electromagnetic clutch while rotating the truck delivery screw by the front-side driven roller until the roller arrives at a fixed position in the truck delivery screw.