For a serial color ink jet printing apparatus that forms an image using a symmetric printing head that ejects large dots and small dots, the configuration of a printing head is provided for suppressing, to the extent possible, a cyclic fluctuation in the main scanning direction. According to the present invention, individual nozzle arrays are arranged so that two nozzle arrays, i.e., a cyan nozzle array c1 and a magenta nozzle array m1, that are located nearer each other, form dots on adjacent scan lines. With this arrangement, a high quality image, having neither an uneven density nor an uneven color, can be formed when a printing head is inclined, or when a cyclic shift in printing positions occurs, depending on the position of the main scanning direction.