A seat air conditioner is applied to a seat disposed in a vehicle interior space and includes a seat back portion which supports an upper body side of a user and a seat cushion portion that supports a lower body side of the user. The seat air conditioner includes multiple air flow ducts provided in at least one of the seat back portion or the seat cushion portion and define an air flow passage for air to be blown out from the seat or air to be drawn into the seat. Some of the multiple air flow ducts are configured to be independent from the other air flow ducts such that air, which is different in temperature from the air flowing through the other air flow ducts, is allowed to flow through the some air flow ducts.