A document processing apparatus includes a region extracting unit that extracts a plurality of regions in a document image, a recognition unit that recognizes a character string, a conversion unit that converts the recognized character string, a setting unit that sets first boundary lines that surrounds the document image and at least one second boundary line in a space between adjacent regions of the plurality of regions, an enlargement/reduction unit that moves in parallel at least one line of the first and second boundary lines under a restraint condition that at least one line does not intersect any of the plurality of regions, and enlarges or reduces at least one of the regions in accordance with the parallel movement so long as each region does not get out of a cell; and an insertion unit that inserts the converted character string into each of the regions.