A four-wheel drive vehicle having a front- and rear-wheel engaging mechanism designed to enable differential limiting means provided between the front and rear wheels to be controlled over the range from the direct coupling position to the disengaged position through the slip region by the control of the degree of engagement. The vehicle is provided with engaging means for driving the front- and rear-wheel engaging mechanism at a set degree of engagement, wheel acceleration detecting means, reference acceleration detecting means, and control means for controlling the engaging means by setting a degree of engagement on the basis of the result of a comparison between the detected acceleration of rotation of the wheels and the detected reference acceleration. Alternatively, the vehicle is provided with engaging means for driving the front- and rear-wheel engaging mechanism at a set degree of engagement, acceleration detecting means for detecting accelerations of rotation of the front and rear wheels, and control means for controlling the engaging means by setting a degree of engagement on the basis of the result of a comparison between the detected accelerations of rotation of the front and rear wheels. Thus, when the occurrence of slip is detected, the degree of engagement of the front- and rear-wheel engaging mechanism is controlled in accordance with the degree of slip. Accordingly, it is possible to effectively prevent the vehicle from slipping.