We studied the impacts of soil surface hardness and increased machinery body mass by the harvested crop relative to the fuel efficiency during traveling and driving for head-feeding combine harvesters. The fuel efficiency during traveling and driving increased with softness of the soil, showing a strong correlation with the index of hardness indicated in the Yamanaka model soil penetrometer. The index of hardness realizing fuel efficiency equivalent to traveling on the road was about 23 mm. Based on the fuel efficiency and index of hardness obtained in the testing, a relational expression between the index of hardness and fuel efficiency of the machinery provided for the testing was then figured out, thereby making it possible to correct the fuel efficiency during traveling and driving under any soil conditions. We also confirmed that fuel efficiency during traveling and driving increased with the mass of rough rice in the grain tank. We devised methods of testing and evaluating the fuel efficiency during traveling and driving, by correcting such conditions so as to make a fair comparison among different models.