A clutch actuator unit that includes an abrasion compensation device and removes an adhesive force between a clutch disc and a flywheel by using a diaphragm spring to press the clutch disc against the flywheel and by using a fork to push a first side of the diaphragm spring may include an outer member including a groove and a female screw portion, a push rod pushing against a first side of the fork, an inner member including a male screw portion screwed into the female screw portion, including a rotation center portion of a rear end portion thereof in which a support portion is formed, and including a first gear portion, a fixed guide member guiding the outer member, a pushing member including a second gear portion meshed with the first gear portion, an actuator employing an actuator rod to push or pull the pushing member, and a controller controlling the actuator.