A data processing apparatus uses a pattern table arranging binarizing patterns correspondingly to positions of a pixel, each of which is used for a binarization process in which an arrangement of a number of dots depending on a value of multi-valued image data corresponding to the pixel is determined, to select the binarizing pattern depending on the position of the pixel and on the value of multi-valued image data corresponding to the pixel for executing the binarization process. The pattern table corresponding to one of the values to be taken by the multi-valued image data includes a plurality of types of binarizing patterns which determine different arrangements of dots from each other. The arrangement of each of the plurality of types of binarizing patterns in the pattern table corresponding to the one value has a characteristic that the arrangement is aperiodic and that low frequency components are fewer than high frequency components.