A parking brake apparatus may include: a motor unit; a driving unit operated by the motor unit; a nut screw rotated by the driving unit; a bolt screw coupled to the nut screw so as to pass through the nut screw, and moved in a longitudinal direction inside the nut screw in connection with the rotation of the nut screw; a cable having one side connected to the bolt screw; a hook part connected to the other side of the cable; and a boot part having an internal space in which the cable and the hook part are moved in the longitudinal direction, and including a stopper arranged on a moving path of the hook part so as to restrict the movement of the hook part.