A vehicle control center (20) receives a detected traveling distance received from an on-vehicle terminal device (10) and integrates changes in detected traveling distance to thereby calculate an integrated traveling distance (La) for sequential storing and retaining. Integrated traveling distances (La(1), La(2),.. La(n)) up to the present are used to estimate the subsequent vehicle traveling distance. Mails are provided in advance according to this estimated vehicle traveling distance to inform in advance to on-vehicle terminal devices (10) and a computer (60c) in a sales firm information about vehicle-related information such as an oil changing time. Therefore, it is possible to provide well in advance information to a vehicle based on vehicle condition information received from the vehicle. In addition, changes in detected traveling distance in a vehicle will not affect those concerned.