To provide a method and a device for drying a muddy substance, and a dispersion device capable of dispersing a muddy substance generated in the fermentation industry or the like in a dispersion liquid and efficiently drying the muddy substance.

In the method of drying a muddy substance by a spray dryer, the muddy substance is dispersed in the dispersion liquid before the spray dry so that the fluidity is such that a spray nozzle of the spray dryer is not plugged, and is spray- dried as the slurry. The device of drying a muddy substance is used in the method. The dispersion device 1 for dispersing a muddy substance comprises: (1) a pipe for introducing the muddy substance into the device, (2) a pipe for mixing the dispersion liquid before the muddy substance is introduced into the device, (3) a force-in part 10 for forcing in the muddy substance, (4) a porous plate 12 for pushing the muddy substance out in the shape of a bar, (5) a shearing machine for shearing the pushed-out bar-shaped muddy substance into chips, (6) a reservoir 15 for reserving the mixture of the chipped muddy substance and the dispersion liquid, (7) an agitator 16 for agitating the mixture, and (8) an outlet from which the slurry in which the muddy substance is dispersed flows out.