Patent ID: 7328096

Claim:
A driving force switching control apparatus provided in a four-wheel drive vehicle which has at least one power source and which runs by two-wheel drive or four-wheel drive in accordance with a running state of the vehicle, the apparatus comprising: a constant speed running determining device for determining whether the vehicle runs at a constant speed; a road surface condition computing device for computing a road surface condition by using rolling resistance when the vehicle runs; and a drive system determining device for determining a drive system of the vehicle when it is determined by the constant speed running determining device that the vehicle runs at a constant speed, wherein the drive system is determined to be one of the two-wheel drive and the four-wheel drive in accordance with a computed result of the road surface condition computing device, wherein: the drive system determining device changes a threshold value for switching between the two-wheel drive and the four-wheel drive in a manner such that a determination area where the four-wheel drive is selected increases according to increase in the rolling resistance.