1. A printing apparatus which uses a printhead having a plurality of printing elements, divides the plurality of printing elements into a plurality of blocks, time-divisionally drives the plurality of printing elements, and prints a halftone image on a printing medium in accordance with a result obtained by performing digital-halftoning for input multi-valued image data in each matrix of a predetermined size, comprising: scanning means for reciprocally scanning the printhead; convey means for conveying the printing medium in a direction different from a scanning direction of the printhead; and printing control means for controlling to print a halftone image in each matrix, wherein an arrayed direction of the plurality of printing elements is a convey direction of said convey means, and said printing control means controls printing of the halftone image so as to set a size of the block to be equal to or an integral multiple of a size of the matrix in the convey direction.