A power supply unit for an aerosol inhaler includes: a power supply; a first DC/DC converter; a second DC/DC converter; and a circuit board. As viewed from a first direction perpendicular to a surface of the circuit board on which the first DC/DC converter and the second DC/DC converter are mounted, at least a portion of the circuit board includes: a connection portion; a first portion extending from the connection portion in a second direction perpendicular to the first direction; and a second portion extending from the connection portion in a third direction perpendicular to the first direction and the second direction. The first DC/DC converter is mounted on the first portion, and the second DC/DC converter is mounted on the second portion.