The invention relates to an actuator (1; 1a; 1b) which can be moved from an initial position into a working position having at least one actuator element (2; 2a; 2b) whose dimensions can changed by an electrical signal, Appropriately, at least two restoring means (20, 30; 20a, 30a; 20b, 30b) acting on the actuator element (2; 2a; 2b) are provided for movement into the working position. With the at least two restoring means, a total restoring means characteristic curve, which is composed of portions of the individual, preferably preloaded restoring means as well as a portion of a variable stiffness of the actuator element, can be advantageously tailored.