A fuel-saving management system allowing fuel-saving management and associated driver assistance. The system includes, mounted on a vehicle, information detectors detecting various information on the driving state of the vehicle, an information processor, in addition to processing the information detected by the information detectors, generating a warning when processed information satisfies required warning conditions, and an information storage device storing the processed information. In this system, when either a time during which the processed information is maintained to satisfy the required warning conditions, or an elapsed time of the processed information exceeds a previously set time, the information processor stores the occurrence of this overtime event into the information storage device. A setter allowing modification of the required warning conditions, and a printer outputting the information relating to the processed information are also mounted.