To obtain a high-precision retrieval result by giving higher weighting of words, which are extracted from a plurality of sections with duplication eliminated in a retrieval request that is input from a retrieval request inputting means, than the weighting of words extracted only from any one of sections.

A document retrieval device includes a retrieval request inputting means 11, a retrieval condition generating means 13 and a document retrieving means 14, and extracts, from a plurality of documents that are objects to be retrieved in a document database 15, a document that meets the retrieval request composed of multiple sections, at least one of the sections being a sentence. The retrieval condition generating means 13 generates retrieval conditions by giving higher weighting of words, which are extracted from the plurality of sections with duplication eliminated in the retrieval request that is input from the retrieval request inputting means 11, than the weighting of words extracted only from any one of sections. The document retrieving means 13 retrieves, from the plurality of documents that are objects to be retrieved, a document that meets the retrieval conditions generated by the retrieval condition generating means.

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