1. A region-of-interest extraction apparatus comprising: an acquisition unit configured to acquire a structured document and a plurality of display coordinates, the structured document including first elements, the display coordinates indicating display positions of the first elements when the structured document is displayed as an image; a first extraction unit configured to extract block regions from the structured document, the block regions including specific second elements of the first elements; a second extraction unit configured to specify one or more third elements displayed on a display screen based on the display coordinates, and to extract, as a display region, displayed parts of the third elements from the structured document; and a third extraction unit configured to extract a region of interest, in which a user is interested, from the structured document, based on relations between the second elements in the block regions and the third elements in the display region.