A data processing method processes data using a processor including N (N is an integer equal to or more than 2) cores and a memory. The data processing method includes: searching a new character as a character whose raster data is not stored in the memory among a plurality of characters specified by character data included in print data to count a count of the searched new characters; generating M (M is an integer equal to or less than the N) threads, wherein the M is a count determined based on the count of the counted new characters among the N; dividing and allocating the plurality of characters to the M threads to generate raster data for the new characters using any one of the N cores for each of the M threads; and rendering the plurality of characters using raster data corresponding to the character data.