The present invention is directed to an actuator capable of retaining an image-shake correcting lens in a position(s) at which a calibration of lens optics can be affected, without additional locking means. The actuator (10) is capable of translating an image-shake correcting lens (16) so as to prevent an image from shaking, and the actuator is comprised of a fixed member (12), a movable member (14) provided with the image-shake correcting lens, supporting means (18) for supporting the movable member, a position detecting means (24, 25) for detecting a position of the movable member, a driving means (20, 22) for translating and rotating the movable member, a plurality of positioning receiving portions (15a) provided on the fixed member, a plurality of positioning contact surfaces (17a) disposed on the movable member and forced by a rotational movement of the movable member to mate and come in contact with the positioning receiving portions so that the movable member can be moved to a calibration position, and a calibrating means (37) for calibrating the position detecting means in response to detection values from the position detecting means that are received when the movable member is positioned at the calibration position.