PURPOSE: To improve the retrieval efficiency of a document even when a document of different kind of language is preserved in a document preservation part.

CONSTITUTION: This document retrieval device is equipped with an input part 1 to which the character string of a key word, etc., is inputted, a magnetic disk 3 which preserves the groups 21-24 of document files of language with different retrieval objects and the groups 30, 40 and 50 of a dictionary file used in document retrieval, etc., main memory 4 which stores a document retrieval program, while, on which the data of a file read out from the magnetic disk 3 is written, a CPU 5 which reads out the dictionary file designated by the input part 1 and reads out the character string of other language in accordance with the key word and performs retrieval on each document file in the magnetic disk 3 based on the key word and the character string, and a display part 2 which displays a document retrieval result.