A writing area of a sample is divided into a plurality of stripes having a width corresponding to an area density of a pattern to be written on the sample with a charged-particle beam. The writing is stopped when writing of at least one stripe is terminated, and a drift amount is measured. An irradiation position of the charged-particle beam is corrected with the use of the drift amount. When the average value of the area density is more than a predetermined value, a stripe has a width smaller than the reference width, and when the average value of the area density is less than the predetermined value, the stripe has a width larger than the reference width. The width of the stripe is preferably a width corresponding to the variation of a drift from the beginning of irradiation with the charged-particle beam.