The invention relates to a waste-heat boiler (3) for a Claus plant, comprising a steam generation chamber that is surrounded by a pressure-proof jacket (14), a long tube bundle (18) of heat exchanger tubes that extend through the steam generation chamber and are inserted into tube sheets (19) at both ends, at least one additional tube bundle (20) of shorter heat exchanger tubes, which are likewise inserted into the tube sheets (19) at their outlet ends and open into an influx chamber (21) at their inlet ends, in addition to a head part (22) that is connected to the tube sheet (19) at the outlet end and is subdivided into sections. The long tube bundle (18) is traversed by a hot process gas that emerges from a combustion chamber (2). The influx chamber (21) is located inside the steam generation chamber and is exposed to a cooler process gas (10) from a catalyst stage (4) of the Claus plant. One tube bundle (18, 20) is allocated to each section of the head part (22). Devices for draining condensed sulphur are connected to the sections.