Data processing unit produces first access target information. Location information obtaining unit obtains first location information indicating the identifier of a data storage device specified by a user, as well as indicating the location of a user-specified directory within the data storage device. Location information producing unit produces second location information indicating the location of a directory that is placed below the user-specified directory and uniquely assigned to the data processing unit. Access target information producing unit produces second access target information, using the location indicated by the second location information as a reference location. Access unit makes access to the target data file in the data storage device.