A vehicle drive force control apparatus is provided that can stabilize the
output of the electric motor even if the engine rotational speed
experiences an acute change. The output of an engine is delivered to the
left and right front wheels through a transmission and also to an
electric generator. The output voltage of the electric generator is
supplied to an electric motor and the output of the electric motor drives
the left and right rear wheels. The drive force control device predicts
if the rotational speed of the engine will decrease or increase acutely
based on the upshifting and downshifting of the transmission and adjusts
the field current of the electric generator up or down before the acute
change in the engine rotational speed occurs.