The micronizing apparatus includes: a body having a transfer space where hydrogel is transferred, and a discharge space where ground hydrogel is discharged; a rotation shaft disposed in the transfer space, wherein at least one screw is formed on an outer perimeter surface of the first rotation shaft, to transfer the hydrogel along a longitudinal direction of the body; a rotor installed on the rotation shaft so as to rotate together with the rotation shaft, wherein a plurality of rotor blades and a plurality of rotor recesses are alternately formed along a circumferential direction on an outer perimeter part of the rotor; and a stator surrounding the rotor with an air gap between the rotor and the stator, which is a predetermined distance between an outside diameter of the rotor and an inside diameter of the stator, and is fixed to the body.