Abstract: An ultrasonic atomizer for liquids comprises a piezoelectric transducer (16) mechanically coupled to an amplitude transformer (20), an atomizing disk (21) mounted to the free end of the amplitude transformer (20), a housing (22) enclosing at least the amplitude transformer (20) and a cap (30) supporting a sieve-like diaphragm (31). The cap (30) is so mounted to the housing (22) that the diaphragm (31) rests on the atomizing disk (21). The cap (30) consists of two mutually concentric cap parts (32, 33) of which one (32) supports the diaphragm (31) and the second (33) serves to mount the entire cap (30) on the housing (22). A spring (36) is so mounted between the two cap parts (32, 33) that the sieve-like diaphragm (31) is held elastically against the atomizing disk (21) and that the opposing force from the spring (36) thereby is transmitted into the second cap part (33) fixed in the housing.