1. A fuel-efficient-driving evaluator comprising a vehicle-data detector for detecting vehicle data items corresponding to evaluation parameters for fuel-efficient driving; a storage unit for storing the vehicle data items; an evaluating unit for evaluating each stored vehicle data item in view of fuel-efficient driving so as to give an evaluation score to the vehicle data item; and a totalizing unit for totalizing the evaluation scores in order to determine total scores, wherein the storage unit, the evaluating unit, and the totalizing unit respectively includes first to N-th storage portions, first to N-th evaluating portions, and first to N-th totalizing portions corresponding to first to N-th preliminarily-set traveling conditions, wherein the fuel-efficient-driving evaluator further comprises: a correction-coefficient providing unit which determines rates of fuel consumption based on the amounts of fuel consumed in the first to N-th traveling conditions and sends the rates as correction coefficients; and a correction totalizing unit which corrects each of the total scores determined by a corresponding one of the first to N-th totalizing portions based on the corresponding correction coefficient and determines a final score.