A power supply unit for an aerosol generation device, includes: a power supply configured to discharge electricity to a first load that heats an aerosol source; a resistance element configured to be connected in series to the first load and configured to detect an electric resistance value of the first load; and a processing device. The processing device performs first discharging control of discharging electricity from the power supply to the first load to generate aerosol, and second discharging control of discharging electricity from the power supply to a series circuit formed of the first load and the resistance element to detect the electric resistance value of the first load; and in a specific period, other than a period when the first discharging control and the second discharging control are performed, the processing device performs third discharging control of discharging electricity from the power supply to the series circuit.