A halftoning device that converts an input pixel signal of 8 bits per pixel into an output pixel signal of r bits per pixel(r 8); a threshold value array storage that stores a threshold value array having a threshold value of 8 bits; and a threshold value expansion unit that expands the threshold value of 8 bits to expanded threshold value of n bits per pixel. A range of the expanded pixel signal output from the gradation correction unit is matched with a range of the expanded threshold value. The output pixel signal is set according to a comparison of the expanded pixel signal with the expanded threshold value corresponding to the threshold value that is selected for each input pixel signal.