PURPOSE: To reduce the equipment cost and maintenance cost a great deal and, at the same time, prevent ignition and explosion in the drying and incineration of water-containing solids.

CONSTITUTION: An incineration raw material is charged into the heat transfer medium fluidized by the compressed and moist air made by utilizing the exhaust gas of a fluidized bed drier 11, and after the drying by the contact with the above mentioned heat transfer medium it is sent with the heat transfer medium to a high speed fluid incineration furnace 1 through a raw material transportation pipe 4 and a raw material subtransportation pipe 14B. In the high speed fluidized bed incineration furnace 1 the incineration of the above mentioned dried incineration raw material is carried out and, at the same time, the heat transfer medium in the exhaust gas of the high speed fluidized bed incineration furnace 1 is caught by a main cyclone 7, and the heat transfer medium that is caught is returned to the above mentioned high speed fluidized bed incineration furnace 1 by a return pipe 6 in order to recycle the heat transfer medium and, at the same time, part of it is recycled to the above mentioned fluidized bed drying machine 11 by a return branch pipe 10.