To increase a heat exchange capacity of an indoor heat exchanger without increasing a pressure loss inside tubes of an outdoor heat exchanger. A heat exchanger is constituted by an indoor machine equipped with an indoor heat exchanger 10 constituted by a plurality of heat transfer tubes 12A, which have a spiral grooves 13A formed with a predetermined lead angle Ra on inner faces of the tubes and are made to pierce a plurality of fins 11, and an outdoor machine equipped with an outdoor heat exchanger 20 constituted by a plurality of heat transfer tubes 22A which have a lead angle Rb of spiral grooves 23A smaller than that of a heat transfer tubes 10A used for the indoor heat exchanger 10 and are made to pierce a plurality of fins 11.