In a file-accessing system for use in an information-processing apparatus, an original file name and its simplified file name constitute one piece of conversion data. One or a plurality pieces of such conversion data are prepared. A conversion rule is prepared from one or more pieces of conversion data. A single conversion rule may be prepared, or a plurality of conversion rules may be prepared. The conversion rule or rules are stored in a conversion rule storage, with each conversion rule in the form of one file. When specific conversion rules are designated, from among the conversion rules stored in the conversion rule storage, they are loaded into a RAM area. When a simplified file name entered by the operator is received by the system, it is converted into its corresponding original file name, with the RAM area examined. In this manner, the file-accessing system enables a file to be accessed with a simplified file name. In addition, since the file name conversion is executed by use only of the specific conversion rule, it is practically impossible for unauthorized persons to use the conversion rule. Therefore, the file can be accessed easily and yet reliable file security is ensured.