To provide a jet-burner type treatment device which carries out a treatment making use of a jet gaseous body blown off from a jet burner, wherein a material to be treated which has a property to forms a dehydrated surface skin for sealing the moisture of a core portion therein due to compositions contained in the material is promoted to come into contact with a thermal gaseous body and a fluidized condition of the material to be treated is also improved so that the material to be treated can be reliably treated and the material produced by the treatment can have the homogeneous quality.

A feed opening 10 is provided such that it can feed a material 9 to be treated in a direction which substantially opposes a flow direction of a flame jet stream 8 blow off from a Jet burner 2 mounted on a treatment vessel 1. The material 9 to be treated is forcibly extruded from the feed opening 10 by weans of a screw conveyor 11. The feed opening 10 can be elevated a distance S by means of elevating means 12 so as to make the feed opening 10 feed the material to be treated to a given position in the flame jet stream 8. Furthermore, the feed opening 10 may have a large number of apertures through which the material 9 to be treated can be extruded and may be formed in a conical shape which follows the flow direction of the flame jet stream 8.