PURPOSE: To shorten a retrieving time and to prevent erroneous retrieve by providing a retrieve result judging means to judge the presence and absence of the same individual in different names and the different individuals in the same name from retrieved client information.

CONSTITUTION: An input data checking part 13 checks the validity of input data inserted from a keyboard 11. A key judging part 14 judges whether the inputted retrieve key is a client code or a name/date of birth, and a key converting part 15 converts the same when the inputted retrieve key is the name/date of birth. Further, a data base retrieving part 16 retrieves the client information corresponding to the retrieve key inputted by a data base 17, and a retrieve result judging part 18 judges the presence and absence of the same individual in the different names and the different individuals in the same name from the retrieved client information, and edits the client credit information retrieved by an output data editing part 19 to an output format. Thus, the retrieving time can be shortened, and the erroneous retrieve can be prevented.