An aerosol-generating device (100, 200) comprising: a heater configured to heat an aerosol-generating material; a puff detection sensor configured to detect puffs of a user; a battery (120, 220) configured to supply power to the heater; and a controller (110, 210) configured to: based on a new puff being detected by the puff detection sensor, count a number of accumulated puffs including the new puff, determine a puff section type (400, 410, 420) corresponding to the number of accumulated puffs, from among a plurality of puff section types (400, 410, 420) which are divided according to the number of accumulated puffs, and control the power supplied to the heater based on a power range preset for the determined puff section type (400, 410, 420), wherein when a first puff series starts within a first puff section, the number of puffs counted during the first puff section is less than a threshold puff number, the controller (110, 210) is configured to set the power supplied to the heater to a first power value; and when a second puff series starts after a threshold time has passed from when the first puff series ends, the controller (110, 210) is configured to set the power supplied to the heater to the first value. a heater configured to heat an aerosol-generating material; a puff detection sensor configured to detect puffs of a user; a battery (120, 220) configured to supply power to the heater; and a controller (110, 210) configured to: based on a new puff being detected by the puff detection sensor, count a number of accumulated puffs including the new puff, determine a puff section type (400, 410, 420) corresponding to the number of accumulated puffs, from among a plurality of puff section types (400, 410, 420) which are divided according to the number of accumulated puffs, and control the power supplied to the heater based on a power range preset for the determined puff section type (400, 410, 420), wherein when a first puff series starts within a first puff section, the number of puffs counted during the first puff section is less than a threshold puff number, the controller (110, 210) is configured to set the power supplied to the heater to a first power value; and when a second puff series starts after a threshold time has passed from when the first puff series ends, the controller (110, 210) is configured to set the power supplied to the heater to the first value. based on a new puff being detected by the puff detection sensor, count a number of accumulated puffs including the new puff, determine a puff section type (400, 410, 420) corresponding to the number of accumulated puffs, from among a plurality of puff section types (400, 410, 420) which are divided according to the number of accumulated puffs, and control the power supplied to the heater based on a power range preset for the determined puff section type (400, 410, 420), wherein when a first puff series starts within a first puff section, the number of puffs counted during the first puff section is less than a threshold puff number, the controller (110, 210) is configured to set the power supplied to the heater to a first power value; and when a second puff series starts after a threshold time has passed from when the first puff series ends, the controller (110, 210) is configured to set the power supplied to the heater to the first value.