An aerosol generating apparatus with interchangeable parts is disclosed. The aerosol generating apparatus includes a holder for accommodating a structure plate and an oscillation generator. The structure plate includes an inlet surface, an outlet surface, a projection extending from the face of the inlet surface, and a through hole. The through hole penetrates the structure plate. The oscillation generator is coupled with and vibrates the structure plate. A reservoir for providing a liquid medicament is also disclosed. The reservoir is detachably engaged with the holder and includes a membrane with a plurality of orifices. During aerosolization, the liquid medicament passes through the plurality of orifices. When the reservoir is engaged with the holder, the membrane of the reservoir is in contact with the projection extending from the face of the inlet surface. In addition, the oscillation generator vibrates the membrane through the projection on the inlet surface. As such, the liquid medicament aerosolizes and ejects via the outlet surface of the structure plate.