An atomizer includes: an enclosed reservoir defining an inner space adapted to receive a liquid therein; a jet nozzle provided in the inner space for passage of an air jet therethrough; a jacket sleeved around the jet nozzle to define a fluid-introducing gap therebetween, the fluid-introducing gap being in fluid communication with the inner space for passage of the liquid therethrough; a mist-discharging conduit extending sealingly into and in fluid communication with the inner space and aligned with the jacket in a jet-ejecting direction; and a compressible member connected to the mist-discharging conduit and the jacket and compressible in the jet-ejecting direction. The jacket, the compressible member, and the mist-discharging conduit are an integrally formed single piece.