PURPOSE: To speed up the operation of the document retrieval device greatly by finding the evaluated value of each document by an analog arithmetic means by using key word relativity indicating the strength of relation between key words and the relation between key words and the document.

CONSTITUTION: This device is provided with a 1st storage means 10 which holds the strength of relation between key words, a 2nd storage means 12 which holds the relation between key words and documents, and a key word connection selecting means 4 which selects a key word connection according to retrieval conditions and converts it into an analog signal. Further, the device is provided with analog arithmetic means 16-1 - 16-m which calculate document likelihood by using the value of the key word connection in the form of the analog signal and converting means 18-1 - 18-m which convert the calculated document likelihood into a digital value. Consequently, the document likelihood is calculated by an analog circuit and fuzzy retrieval is performed fast.