An aerosol generating device includes a first vaporizer configured to generate a first aerosol by heating a first liquid composition, a second vaporizer configured to generate a second aerosol by heating a second liquid composition, and a controller controlling power supplied to the first vaporizer and the second vaporizer, based on a first mode, in which a smokeless aerosol is generated, and a second mode, in which a transport amount of nicotine included in the second liquid composition is adjusted.