The power supply apparatus for sliding door 100 includes the vehicle body side fixing member 110 provided in the guide rail receiving portion 143, the bracket side fixing member 120 provided in the bracket 151, the wiring body 130 for supplying power from the vehicle body 140 side to the sliding door 150 side and the running member for bracket 160 for running and holding the wiring body 130 on the back surface of the bracket 151. The wiring body 130 is held with the vehicle body side fixing member 110 and the bracket side fixing member 120, and is arranged to run on the back surface of the bracket 151 with the running member for bracket 160.