PURPOSE: To provide an accurate differential control property according to the change in a specific condition without providing a number of control map groups by providing a first control map for rapidly increasing the differential control force from the time of low differential rotation, by providing a second control map for smoothly increasing the differential control force, and by choosing the control maps according to a specific condition.

CONSTITUTION: A first control map having a first differential control characteristic curve for rapidly increasing the differential control force from the time of low differential rotation, and a second control map having a second differential control characteristic curve for smoothly increasing the differential control force, are provided on a control unit 43 for differential gear. The car wheel velocity of front and rear wheels 16, 18 in the left and right is calculated based on the input signal from each car wheel velocity sensor 30, to calculate the differential rotation speed for each differential gear. The differential control force for each differential gear is calculated based on the calculated value of the differential rotation speed, and the control current value to be supplied to the solenoid of an electromagnetic multiple disc clutch is calculated.