A power supply unit for an aerosol inhaler includes a power supply dischargeable to a load for heating an aerosol generation source, a first sensor configured to output a signal indicating an aerosol generation request, and a processing device configured to acquire the signal. The processing device causes the power supply unit to operate in a first mode in which a maximum power consumption amount is a first amount and a second mode in which a maximum power consumption amount is smaller than the first amount, 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, and causes the power supply unit to operate such that a maximum power consumption amount is less than the first amount at a timing before the period exceeds the predetermined time in the first mode.