To remove a black defect on the side of a stencil mask and perform a black defect correction that prevents a white defect film from depositing from the side and a sag on the side thereof without slanting a stage.

The side of the stencil mask is selectively scanned by a grazing incidence ion beam or an electron beam 5 which is focused by a condenser lens 1 and deflected by a deflector 2a, which is above an objective lens 3, and forms a locking point 6 in the vicinity of the stencil mask by swinging back the objective lens 3. In the case of a black defect, the defect is removed by physical sputtering or gas assisted etching. In the case of a white defect, scattere containing carbon is formed on the mask for EPL by FIB-CVD or electron beam CVD from the side, and scattere containing platinum is formed on a mask for IPL, thus the defects being corrected. The above method is applied to a portion where the black defect is corrected by a vertical incidence ion beam (a portion that has a sag in a cross section), and the side is weighed according to the length and selectively scanned for the removal of the sag.