Abstract: The machine for performing in-line treatment on containers comprises a treatment enclosure with a loading path for loading a row of containers and an unloading path for unloading a row of containers, the two paths being distinct from each other, and a carrousel of the first-in-first-out type, which carrousel firstly includes a plurality of mutually equidistant successive moving rails, each rail being designed to receive one row of containers, and means for moving the set of moving rails, and secondly is mounted inside the enclosure so that successive rows of containers can be transferred from the loading path to the unloading path of the enclosure. The carrousel is further equipped with regulation means which are designed to cause the set of moving rails to advance in successive steps at a given rate so that the transit time taken by each rail to travel from the loading path to the unloading path is substantially equal to a predetermined duration.