Abstract: A drying plant utilizing a flame jet comprises a jet burner supporting device which is provided over a treatment tank, and a sound arresting device which is formed at a burner inserting port in the upper surface of the treatment tank. A jet burner drawn out of the treatment tank is inclined to bring the fore end of the burner close to an ignition device, thus to ignite the burner. While observing the ignited burner externally through a transparent tube, combustion is controlled to establish the perfect combustion. Loud noises at the adjustment of the combustion are prevented by the sound arresting device from being given forth to the outside. A matter to-be-dried, such as paper manufacture sludge, supplied into the treatment tank is crushed by flames of the jet burner at high temperature and at high speed without being burnt. The treated matter is taken out as the dried matter.