A vaporizer includes: a liquid storage for storing liquid composition； an upper cap portion coupled with the liquid storage and having a cavity for introducing the liquid composition of the liquid storage； a lower cap portion coupled with the upper cap portion to form an aerosol-generating space； a liquid delivery element positioned in the aerosol-generating space between the upper cap portion and the lower cap portion, and configured to absorb the liquid composition transferred from the liquid storage； a sealing portion having a coupling recess supporting at least one of end portions of the liquid delivery element, positioned between the upper cap portion and the lower cap portion, connected to the cavity, and configured to deliver the liquid composition from the liquid storage to the at least one of the end portions of the liquid delivery element； a heating element configured to heat the liquid delivery element to generate aerosol； and a leg portion extending from the upper cap portion to the lower cap portion, contacting at least a portion of the liquid delivery element, and configured to block a coupled portion between the coupling recess of the sealing portion and the at least one of the end portions of the liquid delivery element to block a flow of the liquid composition from the sealing portion to the aerosol-generating space.
