In order to realize a numerical information retrieving device which permits a user to retrieve numerical information without caring about representations or unit systems, the numerical information retrieving device of the present invention includes an input arrangement for inputting any document to-be-retrieved or any numerical expression to be retrieved, an attribute information dictionary which stores attribute names indicative of attributes and conditions for bestowing the attributes, an attribute bestowal arrangement for bestowing an attribute on the inputted document or numerical expression by referring to the attribute information dictionary, a conversion information dictionary, and a numerical conversion arrangement.