A coupling member configured to bridge outer and inner body portions 3c, 4c in a state of hampering the outer and inner body portions 3c, 4c from being displaced in directions of separating the outer and inner body portions 3c, 4c is constituted by a bridge portion 20a integral with a caliper 5c including the outer and inner body portions 3c, 4c. Further, a brake torque applied to the inner and outer pads 11a, 12a is supported by outer side coupling pins 13a, 13a configured to bridge two end portions of the outer and inner body portions 3c, 4c.