The attaching/removing workability of the collecting vessel of a conditioning apparatus with respect to a port block is increased. A primary-side port and a secondary-side port are formed in a port block 13, and a female screw part 27 that is screwed to a male screw part 23 is provided to the collecting vessel 24 that is mounted to the port block 13. An annular lock member 31 is mounted to the opening end of the collecting vessel 24 so as to be movable in the axial direction. A tongue piece 38 that presses the annular lock member 31 towards the outside in the axial direction of the collecting vessel 24 is provided to the inside of the annular lock member 31. A movable-side engagement part 41 that engages a fixed-side engagement part 42 of the port block 13 when the collecting vessel 24 is rotated to a position of fastening completion is provided to the annular lock member 31.