Abstract: An improved corrugating roll unit exchanging apparatus for a single facer is disclosed. Guide rails directed in an axial direction of corrugating rolls are disposed horizontally above a single-facer. One end of a beam is supported so as to be movable along the guide rails, and the other end thereof is supported by posts which are horizontally movable in the axial direction of the corrugating rolls. A suspending device for suspending a corrugating roll unit is held by the beam. Preferably, the beam is supported by the guide rails via drive wheels. Further preferably, the posts are formed in a gate shape, and the lower ends of the posts are supported by driven wheels adapted to roll along a pair of parallel rail tracks.