To obtain a data which is necessary for diagnosis without using a drive recorder which is a high cost by providing with a start switch for transferring a signal for starting the record of a vehicle data and a means for displaying an inner condition, and recognizing the remaining rate of a content volume simply simultaneously with selection of a necessary information.

In the case where initiating of a communication condition with a vehicle is completed and a self diagnosis code is generated, or in the case where a manual trigger by a start switch or an outer start switch 13 is identified, the record of a vehicle data is started. After the vehicle data is recorded for a prescribed time, the record is completed temporarily, the light such as 'REC' is lightened in a LED displayer 7, and it is known that the record is completed. The number of the memory data is measured, it is transferred to a trigger waiting condition in the case where the number is a recordable maximum number or less in a data recording means 4, and it waits for taking in next data. In the case where the data having the recordable maximum number is taken in, the light such as 'FULL' is lightened in a displayer 7, and renewal of the update for the future is stopped.