A document processing apparatus has a data exchange processor for inputting plural first structured documents, extracting contents included in the respective first structured documents, and creating second structured documents respectively corresponding to the first structured documents and having a predetermined data structure, a data unification processor for unifying the plural second structured documents into a third structured document, a layout processor for arranging plural rectangles in a predetermined area based on rectangular size information included in the third structured document, and a rendering processor for rendering the contents corresponding to the respective rectangles described in the third structured document.