A printing apparatus configured to carry out printing by discharging an ink onto a recording medium while transporting the recording medium, the printing apparatus comprising: a carriage unit that is disposed facing the recording medium, and that is configured to reciprocate in a main scanning direction, which intersects a transport direction of the recording medium, wherein the carriage unit includes a first head, which includes a plurality of first nozzles that are arranged in the transport direction of the recording medium and configured to discharge the ink, and in an outgoing path in the reciprocation of the carriage unit, the printing apparatus is configured to print a first image on the recording medium using the first head, the carriage unit further includes a second head, which includes a plurality of second nozzles that are arranged in the transport direction of the recording medium and configured to discharge ink of the same color as the first nozzles, and in a return path in reciprocation of the carriage unit, the printing apparatus is configured to print a second image on the recording medium using the second nozzles; wherein the second head is disposed so as to be adjacent to the first head in the main scanning direction, and to overlap with the first head such that the first head is upstream from the second head in the transport direction of the recording medium, wherein, in a region in which the first head and the second head overlap, a third image, which the first head prints on the recording medium, and a fourth image, which the second head prints on the recording medium, in either the outgoing path or the return path, have the same printing densities in each dot row in the main scanning direction and supplement one another, wherein, in the third image the majority of the dots formed are included in a dot group, in which at least two dots formed using the ink that is discharged from the first nozzles are linked to one another in the main scanning direction, and wherein, in the fourth image the majority of the dots formed are included in a dot group, in which at least two dots formed using the ink that is discharged from the second nozzles are linked to one another; characterized in that a printing density of the first image gradually decreases toward an upstream side in the transport direction of the recording medium, and in the first image the majority of the dots formed are included in a dot group, in which at least two dots formed using the ink that is discharged from the first nozzles are linked to one another in the main scanning direction; and the second image supplements a decrease in the printing density of the first image. a carriage unit that is disposed facing the recording medium, and that is configured to reciprocate in a main scanning direction, which intersects a transport direction of the recording medium, wherein the carriage unit includes a first head, which includes a plurality of first nozzles that are arranged in the transport direction of the recording medium and configured to discharge the ink, and in an outgoing path in the reciprocation of the carriage unit, the printing apparatus is configured to print a first image on the recording medium using the first head, the carriage unit further includes a second head, which includes a plurality of second nozzles that are arranged in the transport direction of the recording medium and configured to discharge ink of the same color as the first nozzles, and in a return path in reciprocation of the carriage unit, the printing apparatus is configured to print a second image on the recording medium using the second nozzles; wherein the second head is disposed so as to be adjacent to the first head in the main scanning direction, and to overlap with the first head such that the first head is upstream from the second head in the transport direction of the recording medium, wherein, in a region in which the first head and the second head overlap, a third image, which the first head prints on the recording medium, and a fourth image, which the second head prints on the recording medium, in either the outgoing path or the return path, have the same printing densities in each dot row in the main scanning direction and supplement one another, wherein, in the third image the majority of the dots formed are included in a dot group, in which at least two dots formed using the ink that is discharged from the first nozzles are linked to one another in the main scanning direction, and wherein, in the fourth image the majority of the dots formed are included in a dot group, in which at least two dots formed using the ink that is discharged from the second nozzles are linked to one another; characterized in that a printing density of the first image gradually decreases toward an upstream side in the transport direction of the recording medium, and in the first image the majority of the dots formed are included in a dot group, in which at least two dots formed using the ink that is discharged from the first nozzles are linked to one another in the main scanning direction; and the second image supplements a decrease in the printing density of the first image.