According to one embodiment, a method of adjusting a charged particle beam drawing apparatus includes obtaining an offset amount in beam size to be set in the charged particle beam drawing apparatus. The method includes forming a linear evaluation pattern on a substrate by changing number of divisions of a beam with a predetermined size and performing drawing by using divided beams, obtaining a change amount in a line width of the evaluation pattern from a design dimension for each number of divisions, and calculating the offset amount by fitting a model function to the change amount for each number of divisions, the model function being obtained by modeling a pattern line width based on a distribution of energy given by charged particle beams.