Provided is a method that controls and uniformizes fluidity of ash-free coal. The method includes the steps of obtaining an ash-free coal by removing a solvent from a solution containing a coal component dissolved therein (ash-free coal obtaining step (solvent recovering unit 8)); and mixing a plurality of coals of different types or components thereof, where the coals are capable of individually giving ash-free coals having different fluidities (mixing step (see reference signs B1 to B6)). The ash-free coal obtaining step (solvent recovering unit 8) obtains the ash-free coal by removing the solvent from the solution containing components of the coals which have been mixed.