An edited section information acquisition unit generates edited section information and edited section association information based on edit history information. Pre-edit content/post-edit content correspondence relationship acquisition unit groups consecutive edited groups based on the edited section information of the edited section information acquisition unit and generates group information. An edited section information display screen generation unit generates screen information based on the edited section information and the edited section association information of the edited section information acquisition unit, the group information, inter-group association information, section/group association information of the pre-edit content/post-edit content correspondence relationship acquisition unit, and input information of an input unit. A provision unit displays the screen information obtained by the edited section information display screen generation unit.