A seat air-conditioner is applied for a seat on which an occupant is seated. The seat air-conditioner includes a blower configured to suck air through a supporting surface of the seat that supports the occupant, and an introducing passage through which the air is introduced from the supporting surface to the blower. The seat includes a seat cushion supporting a lower body of the occupant and a seat back supporting an upper body of the occupant. The blower is disposed in the seat back such that airflow generated by the blower flows more through the seat back than through the seat cushion.