1. A document processing unit for displaying a comment written at an arbitrary position in a document together with the document, comprising: document storing means for storing a plurality of document files, each document file having a same document and at least one comment independently written at any position in the document; layout means for combining and laying out the comments in positions where the respective comments correspond to said plurality of document files; display means for displaying the document and the laid out comments; wherein said layout means changes the positions of the comments so that the comments do not overlap with each other; and wherein said layout means obtains a first distance d1 and a second distance d2 by dividing a distance D of an overlapped portion of a first comment and a second comment in a predetermined direction in accordance with the largeness of the first comment and the largeness of the second comment, and moves the positions of the first comment and the second comment by the first distance d1 and the second distance d2.