1. A document processing method for editing a document formed from a plurality of originals, comprising: a first display control step, of controlling a process of displaying a graphic object representing a specific chapter in a source original such that the graphic object moves on a document in response to instructions to drag the graphic object, when moving or copying the specific chapter in the source original on a certain portion of the document; and a recognition step, of recognizing a boundary between chapters in a destination original in the document, near a position of a cursor for dragging the graphic object representing the specific chapter, wherein said first display control step includes controlling a process of displaying a mark for indicating to which areas on both sides of the recognized boundary in the destination original the specific chapter be to belong.