Pistons 3 and 7 are pressed to a friction member 11 at two points that are positioned at a rotating-in side and a rotating-out side in a rotating direction of a brake rotor 10. An axial force control is performed for the piston 3 on the rotating-out side, and a position control based on the position of the piston 3 on the rotating-out side is performed for the piston 7 on the rotating-in side.