To simplify the structure and to reduce the cost, by connecting the both circuits, simultaneously with the assembling a door trim and a door inner panel.

In a structure where a door trim 1 and a door inner panel 2 are assembled through a clip 3, the clip 3 comprises a spring part 6 for pressing a flat harness, and the terminal conductor parts 21a, 22a of the flat harnesses 4, 5 respectively at the door trim side and the door inner panel side, are held between the spring part 6 and the door inner panel 2. The door panel 2 comprises the stopper means 19, 20 to the flat harness 5 at the door inner panel side and the clip 3, and the spring part 6 comprises a stopper means 14 to the flat harness 4 at the door trim side. The clip 3 optionally comprises the second spring part for holding a water-proof inner seal.