A powder based granules disintegrating and sizing device having a drive shaft in a horizontal direction inside a casing, a rotor fixed to the drive shaft, a sizing stator having an inclined surface, a gap section A where the powder based granules settles being formed by the plate surface of the rotor and the inclined surface of the sizing stator, and a disintegrating and sizing section B being formed by the narrowest gap section between the circumferential edge of the rotor and the sizing stator. The drive shaft is supported in a cantilever fashion, the rotor is fixed to an open side end portion thereof, the sizing stator is installed over the whole circumference of the rotor, a raw material supply port is opened in the vicinity of the central portion of the rotor, and a product output port is opened in the vicinity of position directly below the rotor.