The file name (75) of a second data file is included in a first data file (32a). A position information data (76) is likewise included in the first data file (32a) for specifying the position of specific data in the second data file. A processing unit obtains the specific data from the second data file based on the description in the first data file. Specific instructions are supplied to a quality analyzing apparatus in a vehicle quality analyzing system based on the obtained data. The quality analyzing apparatus supplies electronic apparatuses or devices in a vehicle with predetermined signals in response to the specific instructions, so as to analyze the quality of the vehicle based on responses from the electronic apparatuses or devices. A set of independent files is utilized to establish the data structure. Data can be changed or modified in the individual file in a facilitated manner.