Each page image of image data including a plurality of pages is divided into a plurality of areas by block selection, and meta information associated with at least one of the coordinate position, size, and type of each of the plurality of areas is held. As a combining condition, at least a direction to retrieve areas to be combined is set, area combining processing for combining two or more areas which satisfy the combining condition of the plurality of areas of the image data into one area is executed, and information associated with the areas of the image data including the combined area is stored.