The invention provides an apparatus for reproducing the state in which an editor has added and described a comment to a document while what description content the editor is viewing so that the intention of the editor is rendered understandable. A document synthesis unit displays a layer on a screen, the document editing unit generates a new layer based on user operation to the document having the component layer displayed on the screen and adds it to the document, and generates at-add-time layer display state information of the layer displayed on the screen at the time of the addition. Layer state managing units manage the at-add-time layer display state information in correlation with the new layer, and when a display designation receiving unit receives a designation that specifies the content added to the document, a layer state reproducing unit controls the document synthesis unit to display the layer that was displayed on the screen when the specified layer was added based on the at-add-time layer display state information.