An electromechanical brake includes a pair of pad plates provided with a friction pad to apply pressure to a disc, a carrier to support the pad plates, a caliper housing supported movably back and forth on the carrier to apply pressure to the pad plates; and a presser to apply pressure to the pad plates. The presser includes a pressing member to apply pressure to one of the pad plates, a driving motor to operate the pressing member, a gear assembly disposed between the driving motor and the pressing member to transfer rotational force of the driving motor to the pressing member. The gear assembly includes an input shaft connected to a motor, an external gear coupled to the input shaft such that the external gear eccentrically rotates, and a stationary internal gear and a rotational internal gear meshed with the external gear such that the external gear revolves, while rotating. The rotational internal gear includes an output shaft in the center thereof and the output shaft is connected to the pressing member.