A fluid-pressure brake device for a vehicle includes a brake operation member, a master cylinder, wheel cylinders a fluid-pressure control actuator, a fluid-pressure control circuit, and an electric control unit. Moreover, in the fluid-pressure brake device for a vehicle, normally closed electromagnetic open/close valves are interposed on paths for connecting master system fluid-pressure circuits and a drive fluid chamber of the master cylinder with each other, the master system fluid-pressure circuits being configured to connect pressure chambers of the master cylinder and pressure chambers of the wheel cylinders—with each other. The fluid-pressure brake device for a vehicle is configured so that the electromagnetic open/close valves are opened when an action amount of the brake operation member is equal to or more than a set value. As a result, a size and a stroke of each of master pistons in the master cylinder can be reduced.