PURPOSE: To simplify the structure and improve the durability of a multiple- passage rotating union by fitting a rotor means in the axial bore of its housing through a cylindrical sleeve member, shortening the sleeve member relatively and forming the sleeve member with a plurality of holes aligned with fluid inlets.

CONSTITUTION: This multiple-passage rotating union comprises a housing assembly 12 including a housing 13 and a sleeve bearing 14, and a rotor assembly 16 including an outer rotor 17 and an inner rotor 18 rotatably placed in the housing assembly 12. These assemblies 12 and 16 define a labyrinth passage including an outer passage 19 and an inner passage 20. The housing 13 has two fluid inlets 24 and 26, and a vent passage 30 communicating with a drain part 34 in its lower wall 29. The sleeve bearing 14, which is produced to have a relatively short length, has a pair of holes 38, 39 aligned with the respective inlets 24 and 26, and defines annular spaces 36 and 37 communicating with respective inner passages 31 and 33 by both its ends.