PURPOSE: To appropriately carry out slip control by providing a slip judging means to judge the slip condition of each wheel by using the first to third pseudo vehicle speeds.

CONSTITUTION: The wheel speeds of two right and left wheels in the longitudinal direction are compared with each other to find the larger value, and the larger wheel speed is set as the pseudo vehicle speed of the left wheel side or the pseudo vehicle speed of the right wheel side. Thus, even when two left wheels 1,3 or two right wheels 2,4 are both locked during the braking, and the slip is generated against the road surface, the pseudo vehicle speed on the locked wheel side is not mistakenly set to zero. The value where the correction value is subtracted from the third pseudo vehicle speed calculated based on the wheel speed on the unlocked wheel side is set as the pseudo vehicle speed on the locked wheel side, and the calculation of the slip ratio and further the slip control can be more appropriately executed.