To provide a slip ring that can be constituted inexpensively by drastically reviewing points such as inferior assembling performances causing cost increasing factors, and structure of the ring or the like in a slip ring mechanism.

The slip ring is provided which has a constitution that a metal elastic member that is relatively rotatable against the metal cylinder is abutted on the outer periphery of the metal cylinder. The slip ring has total N pieces of conduction passages starting from the conduction passage 1 to the conduction passage N, and is constituted so that a relationship is established in the inner diameters N of the metal cylinders forming arbitrary number of conduction passages N that (N+1)(N) (N is 1 or more).