1. A drawing apparatus which draws a circuit pattern and a mark on a substrate with a charged particle beam based on drawing data, the apparatus comprising: a storage unit configured to store pattern data representing the circuit pattern and mark data representing the mark, respectively; an obtaining unit configured to obtain information associated with a positioning accuracy of the charged particle beam relative to the substrate; a determination unit configured to determine a drawing region for the mark relative to the circuit pattern based on the obtained information; and a generation unit configured to generate combined data by combining the pattern data and the mark data respectively stored in the storage unit such that the mark is drawn in the drawing region determined by the determination unit and convert the combined data into bitmap data, thereby generating the drawing data.