To print a barcode even in a printer having no correction function by using a barcode font, to suppress degradation of quality in printing results by correcting the barcode, as well as to stabilize barcode reading, in using a printer which adopts an ink jet recording system from general application.

An information processor determines whether or not data to be printed include a barcode font (S13). When it is determined that the barcode font is included, bit map image data in which the barcode font is developed are rewritten by pixel to correct a bar width on the basis of a predetermined correction value (S15). Image data including the bit map image data with corrected barcode are output to a printer.