An atomizer includes: a housing provided with an air intake vent, an air discharge vent, and a liquid storage chamber; an atomization assembly disposed in the housing, the atomization assembly being provided with an atomization chamber and a buffer cavity; and an air flow channel communicating the air intake vent to the air discharge vent and passing through the atomization chamber; at least one air exchange passage arranged between the air flow channel and the liquid storage chamber, the air exchange passage being provided with at least two buffer cavities upstream and downstream in a direction extending from the air flow channel to the liquid storage chamber, two adjacent buffer cavities of the at least two buffer cavities being communicated via an air vent. In the two adjacent buffer cavities, a bottom wall of the buffer cavity located downstream is lower than a setting height of the air vent.