A new Beam Delivery System (BDS) has been proposed for a proton therapy project, partially funded, called AMIDERHA. That BDS is characterized by an active scanning system which irradiates target with a pencil beam. The feature of this project was the using of an accelerator Linac with variable final energies and the Robotized Patient Positioning System instead of the traditional gantry. The active BDS of AMIDERHA then does not include a gantry and a pencil beam scanning system with a relatively long Source to Axis Distance (SAD) could be used. In this condition, the using of a unique device capable of scanning the beam for both horizontal and vertical plane in the active BDS of the project is possible. In this contribution this new beam scanning device will be presented. Furthermore, a preliminary design of the device and the trajectory simulations for beam parameter optimization will also be discussed.