Piezoelectric unit, comprising a fluid chamber, a fluid outlet, an actuator, comprising a thin film piezoceramic element and a membrane, acting as a wall of the fluid chamber, and a support element arranged for preventing a supported portion of the actuator from movement in a main direction of actuation movement of the actuator, while allowing such actuation movement on at least two sides of the supported portion, wherein the support element is connected to a unit portion that extends approximately opposite to the actuator.