The invention relates to an actuator apparatus having an expansion unit (10) which has a magnetic shape-memory alloy material (MSM), is designed to interact with an actuating partner and, in response to an induced magnetic flux, executes an expansion movement along an expansion direction and can be oriented along a longitudinal axis, which is determined by the expansion direction, on the actuating partner and has, at one end, an operative section (14, 18) for exerting an actuating force on the actuating partner, wherein pretensioning and/or spring means (22, 24) are associated with the other end of the expansion unit, in particular opposite the operative section, such that, in an operating state in which magnetic flux is not applied, the expansion unit can exert a force, in particular a shear, actuating and/or holding force, on the actuating partner and/or the expansion unit can have a damping effect.
