An actuator for a valve lift controller comprises a case forming a first and second spaces therein. The first space is supplied with lubricating fluid. The actuator further comprises a feed screw mechanism including a cylindrical spindle and a screw, and converts a rotational movement of the spindle to a linear movement of the screw. The spindle includes a first end portion open to the first space and a second end portion closed to the second space therein. The screw straddles borders between an interior of the spindle, the first space, and an external space. The actuator includes a motor unit which is located in the second space and rotates the spindle. The actuator further includes a sealing member sealing a gap between the case and the spindle to separate the first and second spaces.