To provide a high circuit density flat composite slip ring by forming a groove of each electring ring to which copper is made to adhere on an electric contact electrically connected to a mutual connection path by etching.

A copper layer 210 is stacked on a substrate 200, and then plural holes 240 are bored and plated with conductive material or filled with conductive material, and plural layers of photo resists are exposed to ultraviolet rays and developed through a photo tool including a slot for generating plural concentric rings for rings, and then copper is electrocast between the concentric rings to form copper rings 272, 274, 276. The copper thin layer between the bases of the rings is removed by etching to separate the rings and insulate the same, and then each ring to face 8 is flattened by polishing and applied with a photo resist 289. After that, to expose the ring top face, the photo resist 280 is developed. Subsequently, grooves 86 are formed on the top faces of the rings 272, 274, 276 by etching to remove the layer of the developed photo resist 280.