Abstract: An apparatus for treating bulk material such as hot coke or coal by supplying a treating gas thereto includes a container in which the bulk material is situated during treatment thereof. A gas distributor extends into the interior of this container and includes a plurality of coaxial elongated pipes which have open ends in the interior of the container, an elongated bar extending coaxially along the innermost one of said pipes and also having a free end situated in the interior of the container. The ends of the several pipes which are in the container are open and are enlarged while the inner free end of the bar in the container is also enlarged, and a moving structure is operatively connected with at least one of the pipes as well as the bar for axially moving the same relative to each other so as to adjust the positions of the free end of the bar and the open ends of the pipes with respect to each other.