On the wet road surface, if abrupt steering is turned, an accident will occur. The driver may lose control of the steering wheel by sudden side winds. There is no knowing when a terrible accident may occur. Then, it makes it possible about the trajectory tracking control according to change of speed. We derive the trajectory tracking control in consideration of the influence by speed change and the side wind which used the Sliding Mode Control. First, it creates the model in which the road surface carried out situation consideration. Next, when not receiving the cases where it receives speed change, change of a road surface situation, and the influence of a side wind, and those influences, it performs a numeric simulation about each. We show the validity of the trajectory tracking control of the four-wheeled vehicle according to speed change.