A plurality of test patterns that are disposed in a predetermined direction are printed using dot arrays formed along an intersecting direction interesting with the predetermined direction using nozzles included in an overlapping portion of a first nozzle array and a second nozzle array, a plurality of rules lined in the predetermined direction are printed so as to be adjacent to the test patterns using nozzles included in the first nozzle array and the second nozzle array, density correction values are computed according to density of each of raster lines of the test patterns, and the positions of nozzles specified from the positions of rules are associated with the positions of the raster lines for which density correction values are computed.