In one embodiment, a data processing method is provided for generating writing data from design data and registering the writing data in a charged particle beam writing apparatus. The method includes generating the writing data by performing a plurality of conversion processes on a plurality of pieces of first frame data obtained through division of the design data corresponding to one chip, and performing a plurality of preprocessing processes on a plurality of pieces of second frame data obtained through division of the writing data of the chip, and registering the writing data of the chip in the charged particle beam writing apparatus. The plurality of conversion processes are performed in frame-basis pipeline processing, and the plurality of preprocessing processes are performed in frame-basis pipeline processing. The writing data is registered in the charged particle beam writing apparatus on a frame basis.