In a position measuring method, a mask including first patterns to be transferred and second patterns not to be transferred is prepared. The position coordinates of the second patterns are measured with a position measuring apparatus and an inspection system. First position correction data is generated based on the position coordinates of the second patterns. A difference is obtained between the measured position coordinates of the second patterns and the first position correction data is corrected using the obtained difference. Second position correction data is generated from the corrected first position correction data. An optical image including the position coordinates of the first and second patterns is acquired. The position coordinates of the first patterns of the optical image are corrected using a difference between the position coordinates of the second patterns of the optical image and of the second patterns based on the second position correction data.