An electric brake device, in which the rotational drive force of an electric motor (72) drives a first slave piston and a second slave piston housed in a cylinder body and thereby generates brake fluid pressure, an actuator housing (172) is coupled to the cylinder body, and the mechanism housing part (173a) and a brake fluid encapsulating part in the cylinder body are partitioned by a sealing member, the actuator housing having a mechanism housing part (173a) for housing an actuator mechanism (74) for converting the rotational drive force of the electric motor (72) into the linear drive force for the first slave piston and the second slave piston; wherein the electric brake device is characterized in being provided with an interconnecting hole (179) for interconnecting the mechanism housing part (173a) and the atmosphere.