An aerosol generator for generating an aerosol from a fluid, comprising: a vibratable membrane (22) having a first side (24) for being in contact with the fluid and an opposite second side (25), the membrane having a plurality of through holes (26) penetrating the membrane in an extension direction (E) from the first side to the second side, whereby the fluid passes the through holes from the first side to the second side when the membrane is vibrated for generating the aerosol at the second side, each through hole (26) having along its extension direction (E) a smallest diameter (Ds), a larger diameter (DL) that is larger than the smallest diameter and defined by that diameter that is closest to triple, preferably twice said smallest diameter, each through hole having a nozzle portion (32) defined by that continuous portion of the through hole in the extension direction comprising the smallest diameter of the through hole and bordered by the larger diameter of the through hole, characterized in that the ratio of the total length of each through hole (26) in the extension direction to the length of a respective one of said nozzle portions (32) in the extension direction is at least (4), preferably at least (4.5) and most preferred equal to or larger than (5).L'invention concerne un générateur d'aérosol destiné à générer un aérosol à partir d'un fluide, comprenant : une membrane vibrante (22) ayant un premier côté (24) destiné à être en contact avec le fluide et un second côté opposé (25), la membrane ayant une pluralité d'orifices passants (26) pénétrant la membrane dans une direction d'extension (E) du premier côté au second côté, grâce à quoi le fluide traverse l'orifice passant du premier côté au second côté lorsque la membrane est mise en vibration afin de générer l'aérosol au niveau du second côté, chaque orifice passant (26) ayant le long de sa direction d'extension (E) un plus petit diamètre (Ds), un diamètre plus grand (DL) qui est plus grand que le plus pet
