Caliper brake device for vehicle

A caliper brake device for a vehicle, which applies a brake to rotation of a rotary body by sandwiching a first frictional surface and a second frictional surface formed on either side of the rotary body, comprising:

• a brake caliper having a first caliper arm that faces the first frictional surface and a second caliper arm that faces the second frictional surface;
• a movable brake pad that is supported by the first caliper arm and applies a braking force to the first frictional surface by displacing toward the first frictional surface;
• a pressure chamber formed in the brake caliper;
• a diaphragm that expands in accordance with a pressure of the pressure chamber;
• a plurality of pistons that drive the movable brake pad in a rotary axis direction of the rotary body in accordance with the expansion of the diaphragm;
• a guide member that guides a displacement of the plurality of pistons in a right-angle direction relative to the first frictional surface;
• a support mechanism that supports the brake caliper to be capable of displacing in the rotary axis direction of the rotary body;
• and
• a fixed brake pad that is fixed to the second caliper arm and applies a braking force to the second frictional surface in cooperation with the movable brake pad when pressure is supplied to the pressure chamber.