PURPOSE: To permit smooth reaction without troubles with bubbling, the adhesion of reactants on the wall, etc., by providing plural parallelized driving shafts in a horizontal cylindrical vessel in which coal is fluidized by heat-treating coal and a solvent and also by providing a disk rotator and scraping blade to each driving shaft.

CONSTITUTION: In the inside of the horizontal and cylindrical vessel 4 having the raw material supply port 1, the discharge port 2 for heat treatment reaction liquid, and the gas exhaust port 3, the plural parallelized rotary driving shafts 5(a) and 5(b) are provided, the plural disk rotators 8(a) and 8(b) are provided at a right angle to each driving shaft, and the scraping blades 9(a) and 9(b) are provided to the peripheral edge of the disk rotator. Raw materials, e.g., bituminous coal and a hydrocarbon solvent, heated up to reaction temperature by a heating furnace, etc., are supplied from the raw material supply port 1, reacted by heat treatment while being held at a fixed liquid level inside the vessel 4, and then discharged gradually while being mixed uniformly by the action of the scraping blade from the discharge port 2.