There is provided a slide door constant feeding system whose crossover portion of a wire harness does not interfere with a wall portion of a door trim in opening/closing a slide door and which excels in durability. The slide door constant feeding system comprises a door-side feeding fixture having a main part attached to a door trim, a leg member whose one end is attached to the main part and a door-side anchoring section attached to other end of the leg member and anchoring a door-side end of a crossover portion of a wire harness, a body-side feeding fixture attached to a car body and anchoring a body-side end of the crossover portion and the wire harness for feeding power from the car body-side to the door-side. The door-side anchoring section moves in opening/closing the slide door.