A vehicular seat including: a seat back; a temperature regulation unit which regulates temperature of an air blown from a surface of the seat back and has a heat exchanger; and an exhaust passage which exhaust waste air discharged from the heat exchanger toward the outside of the seat, wherein: the heat exchanger and the exhaust passage are disposed inside the seat back; the exhaust passage has an exhaust portion which opens toward the outside of the seat back; and the exhaust portion is provided on a side of the seat back so as to be oriented downward, the side facing a side wall of the vehicle.