The present invention provides a blasting medium picking-apart device comprising: a hopper-shaped container having an upper opening through which a blasting medium is put in; a blade attached to a rotary shaft which is mounted along the central axis of the container, for applying a shear force to the blasting medium when the blade is rotated; a first shearing plate attached to an inner surface of the container for applying a shear force to the blasting medium between the rotating blade and the first shearing plate; an annular horizontal plane fixed to a lower opening of the container; a rotary plate which is attached to the rotary shaft, and is disposed opposite to the horizontal plane with a predetermined space therebetween; a second shearing plate attached to the rotary plate; and a rotation drive section for driving the blade and the rotary plate for rotation via the rotary shaft.