In a 2M-pass printing operation that forms dots including overlapping dots, this invention makes an arrangement to ensure that the number of overlapping dots that are printed in a unit area in pairs of passes each straddling a print medium convey operation executed between an Mth pass and an (M+1)st pass is greater than the number of overlapping dots that are printed in pairs of passes straddling any other convey operation. This arrangement can cause two dots of the overlapping dots to be separated from each other in the event of a print position misalignment, preventing a possible density fall even in a unit area where the largest density reduction is feared to occur at time of the print position misalignment.