The present invention provides an ink jet printing apparatus and an ink jet printing method which are based on the multi-pass printing method using a print head having a plurality of nozzle rows and which enables a reduction in the number of nozzles to be simultaneously driven, allowing ink to be stably ejected. On the basis of the multi-pass printing method of dividing print data into a plurality of pieces by using mask patterns, the mask patterns are offset according to the positional relationship between the plurality of nozzle rows in the print head.