To effectively process the heating of a raw material by disposing a device for taking-in the raw material and a device for discharging the raw material respectively at an upper side and a lower side, which can directly heat the raw material, by connecting the devices with a communicating pipe and by conveying the raw material from the device for taking-in to the communicating pipe and turning over and agitating the raw material before entering the raw material into the device for discharging.

This device is constituted of raw material inlets 18, 40, raw material outlets 19, 41, a device 2 for taking in the raw material, which is formed to directly heat the raw material, a device 3 for discharging the raw material, and a communicating pipe 4 for communicating the raw material outlet 19 of the device 2 for taking in the raw material and the raw material inlet 40 of the device for discharging the raw material. The raw material is agitated and processed while heating it at the communicating pipe 4.