A vehicle includes a wheel speed sensor sensing a vehicle speed V, a
2WD/4WD switch operative to input an instruction to switch between a
two-wheel driving state and a four-wheel driving state, a transfer and an
actuator switching the two-wheel driving state and the four-wheel driving
state, and an ECU driving the actuator. The ECU instructs the actuator to
switch from the four-wheel driving state to the two-wheel driving state
regardless of the switching instruction from the 2WD/4WD switch if the
vehicle tows a trailer and runs in the four-wheel driving state when the
vehicle speed exceeds a predetermined value. Consequently, it is possible
to provide a four-wheel drive vehicle capable of running while towing an
object and also avoiding an increase in the size of the peripheral parts
of driving wheels.