In the exposure data preparation method for charged particle beam exposure in which an exposure object is exposed while dose is adjusted for each pattern, the method including the steps of: classifying a pattern in terms of a target linewidth; setting a standard characteristic showing the relationship between a standard dose and a resultant linewidth of a resist pattern for a group of patterns having the target linewidth; and preparing exposure data by correcting a shape and dose so that a characteristic showing the relationship between dose of each pattern having the target linewidth and a resultant linewidth of a resist pattern follows the standard characteristic.