A disc brake enables a parking apparatus to be operated via actuation of an electric motor (25), thereby permitting easy operation of the parking apparatus. The disc brake comprises a piston (14) to compress a friction pad (12) used for braking of a disc (1), a caliper housing (13) to receive the piston such that the piston moves linearly therein, and having a cylinder section (15) to which a hydraulic pressure for braking is applied, an actuation shaft (23) rotatably installed within the cylinder section, and having a male screw (23b) formed thereon, a compression sleeve (24) installed within the piston to compress or release the piston while linearly moving therein by rotation of the actuation shaft, and having a female screw (24a) formed thereon to engage with the male screw of the actuation shaft, an electric motor to rotate the actuation shaft, a multi-stage reduction gear train (40) to transmit rotational force of the electric motor to the actuation shaft. The multi-stage reduction gear train has a central axis deviated from that of the electric motor, and a shaft connected with a shaft of the electric motor via a power transmission unit (60).