To retrieve an document image by use of character recognition with high accuracy even if false recognition is present.
In this retrieval device, a character recognition part 21 recognizes characters of the document image 31 to generate a text 32, and a reprocess range decision part 25 decides a reprocess range 33. A lattice generation part 26 generates a candidate character lattice from a retrying result of the character recognition of the reprocess range 33, and a character string generation part 27 generates a character string 34 from the candidate character lattice. A text addition part 22 adds the character string 34 to the text 32 to generate a retrieving text 35. An index generation part 23 applies an index to the document image 31 by use of the text 35, and a retrieval part 24 executes the retrieval by use of the index.
NAOI SATOSHI
NISHINO FUMITO
