Piezoelectric actuator having at least three piezo-elements (2a-2d), at least two of which are operated as working elements , which perform a linear forward or backward movement, wherein at least one of the working elements mechanically expands in a longitudinal direction for performing the forward movement and for performing the backward movement, and another of the working elements contracts in the longitudinal direction (L), characterised in that - the piezo-elements (2a-2d) are arranged inside a carriage in a longitudinal direction (L), said carriage performing the movement in the forward or backward direction; - a fixedly arranged counter bearing is provided between two of the piezo-elements (2a-2d), on which counter bearing the piezo elements (2a-2d) are supported during operation, and - a control device is provided which is set up in such a way that: it operates at least one further piezo-element (2a-2d) as a setting element and, in doing so, is controlled in such a way that the whole piezo-element arrangement inside the carriage is mechanically pre-tensioned and the piezoelectric actuator assumes a corresponding zero position as a consequence, and it controls the working elements in a subsequent working phase in such a way that at least one of the working elements mechanically expands in a longitudinal direction (L) for performing the forward movement and for performing the backward movement of the carriage , and another of the working elements contracts in the longitudinal direction (L). - the piezo-elements (2a-2d) are arranged inside a carriage in a longitudinal direction (L), said carriage performing the movement in the forward or backward direction; - a fixedly arranged counter bearing is provided between two of the piezo-elements (2a-2d), on which counter bearing the piezo elements (2a-2d) are supported during operation, and - a control device is provided which is set up in such a way that: it operates at least one further piezo-element (2a-2d) as a setting element and, in doing so, is controlled in such a way that the whole piezo-element arrangement inside the carriage is mechanically pre-tensioned and the piezoelectric actuator assumes a corresponding zero position as a consequence, and it controls the working elements in a subsequent working phase in such a way that at least one of the working elements mechanically expands in a longitudinal direction (L) for performing the forward movement and for performing the backward movement of the carriage , and another of the working elements contracts in the longitudinal direction (L). it operates at least one further piezo-element (2a-2d) as a setting element and, in doing so, is controlled in such a way that the whole piezo-element arrangement inside the carriage is mechanically pre-tensioned and the piezoelectric actuator assumes a corresponding zero position as a consequence, and it controls the working elements in a subsequent working phase in such a way that at least one of the working elements mechanically expands in a longitudinal direction (L) for performing the forward movement and for performing the backward movement of the carriage , and another of the working elements contracts in the longitudinal direction (L). <EOS>