A vehicle seat air-conditioner includes a seat on which an occupant sits, a heat exchanger that adjusts the temperature of a conditioned gas, a blower that supplies the conditioned gas to the seat, a seat covering layer provided on a surface of the seat and facing the seated occupant, and a flow channel provided on an underside of the seat covering layer that pass the conditioned gas that is introduced by the blower. The vehicle seat air-conditioner is adapted to convey heat of the conditioned gas to an occupant side of the seat covering layer by directly blowing out a portion of the introduced conditioned gas to the occupant side of the seat covering layer, and to perform heat exchange with the occupant side of the seat covering layer by circulating a portion of a remainder of the conditioned gas through the flow channel.