An aerosol generating apparatus is disclosed. The apparatus includes a liquid container, an adaptor detachably engaged with the liquid container, and a driving element accommodated by the adaptor. A perforated membrane, through which a liquid can pass through, is disposed at an exit of the liquid container. Moreover, the perforated membrane faces the driving element. The driving element includes a substrate coupled with a piezoelectric element. The substrate includes an aperture that corresponds to the perforated membrane when the liquid container and the adaptor are engaged so as to receive liquid. Moreover, when the liquid container and the adaptor are engaged, the perforated membrane is in contact with the substrate at the proximity of the aperture, which is about the substrate's center. The adaptor is configured to contact the substrate's periphery only. The resulting apparatus generates aerosol at a desired efficiency with less energy needed.