PURPOSE: To eliminate overshoot or response lag by sustaining a feedforward value at an appropriate level through learning effect even upon the variation of brake conditions.

CONSTITUTION: Positive and negative biases are applied, at the time of torque setting, through a primary lag function circuit to produce two decision waveforms A, B which are then compared, at a learning operating section, with a torque detection waveform TD and coefficient modification processing is not performed so long as the torque detection waveform TD does not deviate from the decision bands A and B. When the waveform TD exceeds the waveform A, a processing is performed to lower the coefficient of torque/hydraulic coefficient circuit in a brake hydraulic pressure control circuit depending on the excess area Sa and when the waveform TD deviates from the waveform B, a processing is performed to raise the coefficient depending on the excess area Sb. When the waveform TD deviates from both bands A and B, time constant of torque control circuit is altered depending on the excess area Sa+Sb. The processings of waveform monitoring, coefficient modification, and the like, are learned iteratively.