Abstract: A multi-channel rotary joint, wherein, between the opposed peripheral surfaces of a housing body (1) and a rotary shaft body (2) coupled thereto for free relative rotation, four or more mechanical seals (3) are provided that effect sealing using the relative rotational sliding contact action of opposed end faces (31a, 32a) of stationary sealing rings (32) provided on the housing body (1) and rotating sealing rings (31) provided on the rotary shaft body (2), and the joint has a single rotating sealing ring (31A) that does double duty as the rotating sealing rings (31, 31) for adjacent mechanical seals (3, 3). In this joint, coating layers (10a, 10a) made from a material with a higher heat transfer coefficient and hardness compared to the material of the double-duty rotating sealing ring (31A) are formed on both end faces (31a, 31a) of the rotating sealing ring (31A).