In a four wheel simultaneous control mode when a regeneration cooperative braking is implemented, a pair of electromagnetic control valves 17A, 17B and one of normally closed electromagnetic valves 19FL, 19FR corresponding to regeneration side left and right wheel brakes 5FL, 5FR and normally closed electromagnetic valves 19RL, 19RR corresponding to non-regeneration side left and right wheel brakes 5RL, 5RR are caused to operate to open and close, while the other of the normally closed electromagnetic valves 19FL, 19FR corresponding to the regeneration side left and right wheel brakes 5FL, 5FR and the normally closed electromagnetic valves 19RL, 19RR corresponding to the non-regeneration side left and right wheel brakes 5RL, 5RR are put in inoperative states in which the valves concerned are kept closed, and all normally open electromagnetic valves 18FL, 18RR, 18FR, 18RL are put in inoperative states in which the valves concerned are kept opened.