Abstract: A reflow furnace includes a suction pipe extending within a heating region along a rail on which a conveyor travels. Suction ports are formed on the inner side of the suction pipe. Flux fumes inside the reflow furnace are sucked into the suction ports and transported to the exterior of a tunnel of the furnace by the suction pipe. The flux fumes are removed by a flux fumes removal apparatus on the exterior of the tunnel, and cleaned gas is returned to the interior of the tunnel at the entrance and the exit of the tunnel, where it forms air curtains which prevent the ingress of outside air.