A structure for attaching a motor cylinder device to the body of the vehicle, said vehicle brake system including: an input device via which an operator inputs brake operations; and a motor cylinder device that generates hydraulic brake pressure on the basis of electrical signals based on said brake operations. Said motor cylinder device has: an electric motor that operates on the basis of electrical signals; a driving-force transmission unit that transmits driving force from the electric motor; and a cylinder mechanism that applies pressure to a brake fluid by moving a piston axially by means of the driving force transmitted by the driving-force transmission unit. A mount for attaching the motor cylinder device to the body of the vehicle is provided near the center of gravity of the motor cylinder device. This makes it possible to minimize displacement of the electric brake actuator when subjected to vibration.