To provide a document search device and its method for more surely searching out a read document.

This document search device is provided with extraction parts 4, 6, and 8, which individually extract a UUID, a characteristic amount and a search word from read image, and search parts 10, 12, and 14 searching and extracting respective corresponding databases 20, 22, and 24 by using the extracted UUID, characteristic amount, and the search word as keys. When the read image is formed by scanning a document, an extraction processing control part 2 carries out combined search processing based on the extracted UUID, characteristic amount, and the search word. A search result evaluation part 16 displays document information specified by the search result on a screen of a display part 18.