Abstract: Disclosed herein is an electronic disc brake. The electronic disc brake includes a carrier on which a pair of pad plates are mounted, a caliper housing, which is slidably installed on the carrier and is provided with a cylinder having a piston mounted therein, a pressure device installed within the cylinder, the pressure device converting rotational motion into rectilinear motion to press and release the piston, the pressure device having an output key which protrudes by penetrating a rear wall of the caliper housing, a motor mounted on an outer surface of the caliper housing to generate drive force, a reducer coupled with a rotary shaft of the motor to amplify the drive force, and a coupling interposed between the reducer and the pressure device to transmit the amplified drive force to the pressure device, wherein the motor, the reducer, and the pressure device are coaxially connected in series.