The invention relates to a cleaning unit for cleaning at least one head section of a teat cup. Said cleaning unit comprises a chamber that has a substantially circular cross-section, is delimited by a wall and has an opening delimited by a sealing element. The chamber has at least one inlet. The cleaning unit is characterized in that at least one section of the sealing element or at least one section of the wall adjoining the opening and a section of the sealing element is or are flexible around the circumference of the chamber.
