Piezo actuator with protection from environmental influences

A piezo actuator with protection from influences of the environment comprises a layer stack (1) made of piezoelectric material layers (10) and arranged in between electrode layers (20). Furthermore, the piezoelectric actuator includes first and second material layer (31, 32) of a respective material that has the electrode layers when a voltage (20) has a lower expansion than the piezoelectric material layers (10), and a cover layer (50) consists of a material of metal. The layer stack (1) is between the first and the second material layer (31, 32) arranged. The outer layer (50) surrounding the layer stack (1) and to the first and second material layer (31, 32) by sputtering.