To obtain an apparatus for deciding abnormality of a yaw rate sensor based on the difference between an actual variation rate of yaw rate detected through a yaw rate sensor and a reference variation rate of yaw rate in which abnormality of a yaw rate sensor can be decided accurately even during control of the difference of brake power between left and right wheels of a vehicle.

A reference variation rate of yaw rate γ'REF is determined depending on a variation of steering angle θs' and the reference variation rate of yaw rate γ'REF is set higher during control of the difference of left and right brake power (shown by a solid line) than other case (shown by a dashed line). According to the arrangement, a normal yaw rate sensor is prevented from being decided abnormal due to increase of actual variation rate of yaw rate caused by control of the difference of left and right brake power.