PURPOSE: To enhance the functional reliability of a rotary medium carrier comprising a large number of partitioned supply sections for carrying a gaseous or liquid medium to a rotator and a discharging section disposed at the supply section by preventing hydrostatic overregulation even in case of multiple annular chambers.

CONSTITUTION: A packing is composed of seal members 55, 60 comprising outer supporting rings 72, 73, and at least one inner flexible ring 68 thinner than a supporting ring formed integrally as a seal lip 69 wherein the supporting rings 72, 73 are applied tightly to a stator and the inside diameter of the flexible ring 68 is smaller than the diameter 78 of a rotor 2 to be surrounded before they are assembled. When the seal lip 69 is fixed, it is bent inward of an annular chamber belonging to that seal lip while surrounding the rotor 2 medium- tightly.