A method for regenerating an NOx removal catalyst, which includes connecting an upstream fixing member (10) to one end of a member to be ground, and connecting a downstream fixing member (20) to the other end; connecting a mixing part (40) for mixing an abrasive with a gas to an upstream portion of the upstream fixing member, and disposing a screen member in the expanded part, and connecting a classification part (70) and a dust-collecting part (80) to the downstream fixing member; and transferring the abrasive which has been mixed with the gas from the mixing part to the upstream fixing member, reducing the flow rate of the mixture in the expanded part, subsequently, causing the mixture to pass through the through-hole of the NOx removal catalyst and the downstream fixing member, and then collecting dust by means of the dust-collecting part via the classification part.