A stringer combining apparatus includes a stringer combining guide section. The guide section has an outer guide member located at the junction of guide groove portions which in combination constitute a Y-shaped guide groove, the member being made resiliently movable in the outward direction, thereby allowing the passage of even members other than fastener elements attached to a stringer. The apparatus further includes a conveyor device for conveying the stringers through the guide section. The guide section is made movable in the direction parallel with the moving direction of the stringers. The guide section is moved by a fluid-pressure cylinder device. Alternatively, the guide section is pressed by the action of a spring toward the downstream side in terms of the conveying direction of the stringers and is maintained at a predetermined operation position by a stopper against the pressing force of the spring and is further made movable against the pressing force of the spring when a force of a predetermined magnitude acts on the guide section toward the upstream side.