A method of measuring beam positions of multi charged particle beams includes acquiring a number of multi charged particle beams needed for the measurement reproducibility of a current amount to be within the range of an allowable value. The method further includes setting measurement points depending on a desired dimensional accuracy value in an irradiation region irradiated by the whole of the multi charged particle beams, and setting, for each of a plurality of measurement points, a beam region, including a measurement point of measurement points irradiated by a plurality of beams whose number is the number of beams needed for the measurement reproducibility in the multi charged particle beams. Further, the method includes measuring, for each of a plurality of measurement points, the position of a measurement point concerned in a plurality of measurement points by using a plurality of beams of a corresponding beam region.