To provide a brake device wherein by wearing of a friction material, contamination of the periphery is eliminated, and in the case of using as the brake device for a vehicle, making intelligent is easily attained of a brake function.

A device comprises a rotary pump 2 forcedly feeding liquid to a delivery side from a suction side when an input shaft 2a is driven to rotate, rotation transmitting means 11 transmitting rotation a rotary shaft 7 to the input shaft 2a, closed flow path 13 connecting one end to a delivery port 2c of the rotary pump 2 also the other end to a suction port 2b thereof to return a liquid delivered from the delivery port 2c to the suction port 2b, electric motor driven variable restriction valve 14 equipped in the halfway of the closed flow path 13, and a control unit 18 controlling a throttle amount of the variable restriction valve 14 in accordance with an operating condition of a brake operating part. Brake force is adjusted by the restriction amount of the variable restriction valve 14.