A power supply unit for an aerosol inhaler that includes an aerosol generation source and a load, the aerosol generation source including an aerosol source and a flavor source to add a flavor component to an aerosol generated from the aerosol source, the load being configured to heat the aerosol source and the flavor source, the power supply unit comprising: a power supply configured to be dischargeable to the load; a first sensor configured to output a signal indicating an aerosol generation request; and a processing device configured to acquire the signal from the first sensor, wherein the processing device is configured to control discharging from the power supply to the load such that a temperature of the flavor source converges to a target temperature, wherein the processing device is configured to cause the power supply unit to operate in a first mode in which a maximum power consumption amount is a first power consumption amount and a second mode in which a maximum power consumption amount is smaller than the first power consumption amount, and causes the power supply unit to operate in the second mode when a period during which the signal is not acquired exceeds a predetermined time in the first mode, wherein the processing device is configured to cause the power supply unit to operate in a third mode in which a maximum power consumption amount is smaller than the first power consumption amount and larger than that in the second mode, and shifts the power supply unit to the third mode at a timing before the period exceeds the predetermined time in the first mode, and wherein in the third mode, the processing device decreases the target temperature lower than that in the first mode, wherein the processing device is configured to control discharging from the power supply to the load such that the temperature of the flavor source converges to the target temperature in the first mode and the third mode, characterized in that the processing device is configured to increase, when the signal is acquired in the third mode, power discharged from the power supply to the load to heat the aerosol source as compared with power discharged from the power supply to the load to heat the aerosol source when the signal is acquired in the first mode without shifting to the third mode. a power supply configured to be dischargeable to the load; a first sensor configured to output a signal indicating an aerosol generation request; and a processing device configured to acquire the signal from the first sensor, wherein the processing device is configured to control discharging from the power supply to the load such that a temperature of the flavor source converges to a target temperature, wherein the processing device is configured to cause the power supply unit to operate in a first mode in which a maximum power consumption amount is a first power consumption amount and a second mode in which a maximum power consumption amount is smaller than the first power consumption amount, and causes the power supply unit to operate in the second mode when a period during which the signal is not acquired exceeds a predetermined time in the first mode, wherein the processing device is configured to cause the power supply unit to operate in a third mode in which a maximum power consumption amount is smaller than the first power consumption amount and larger than that in the second mode, and shifts the power supply unit to the third mode at a timing before the period exceeds the predetermined time in the first mode, and wherein in the third mode, the processing device decreases the target temperature lower than that in the first mode, wherein the processing device is configured to control discharging from the power supply to the load such that the temperature of the flavor source converges to the target temperature in the first mode and the third mode, characterized in that the processing device is configured to increase, when the signal is acquired in the third mode, power discharged from the power supply to the load to heat the aerosol source as compared with power discharged from the power supply to the load to heat the aerosol source when the signal is acquired in the first mode without shifting to the third mode.