A nozzle arrangement structure in an ink jet print head. A plurality of pressure chambers are arranged in circular form, and a plurality of nozzles receive an ink supply from the corresponding pressure chambers and are arranged in an zig zag arrangement to obtain a small interval between the dots. Two straight lines concerning the zig zag arrangement are inclined against a printing direction and a direction perpendicular to the printing direction. When an ink discharge from the nozzles is controlled, preprocessing of serial data is carried out by hardware.