A gas driven anesthesia machine and an integrated manual/mechanical ventilation driving device are provided. The device comprises a movable or deformable external chamber, an internal chamber disposed within the external chamber. The internal chamber has a first port for air communication with outside, and the external chamber has a second port for air communication with outside. The external and internal chambers are configured such that when driving gas enters the space therebetween via the second port, the internal chamber is squeezed by the driving gas so that gas contained therein is delivered via the first port. The external chamber is also adapted to be manually squeezed inwardly to contact and squeeze the internal chamber so that gas is delivered from the internal chamber via the first port. The present invention reduces complexity of circuit design, reduces the number of components used, reduces cost, improves reliability and facilitates the usage.
