A power supply unit for an aerosol inhaler, which causes an aerosol generated from an aerosol source to pass through a flavor source to add a flavor component of the flavor source to the aerosol, includes: a power supply configured to be dischargeable to a first load configured to heat the aerosol source and dischargeable to a second load configured to heat the flavor source; and a processing device. The processing device determines whether the second load can heat the flavor source. When it is determined that the second load can heat the flavor source, the processing device starts or continues discharging from the power supply to the second load as second discharging before starting discharging from the power supply to the first load as first discharging.