To provide an air conditioner capable of reducing an input power and a rotational speed of a fan motor necessary for obtaining a predetermined flow rate from an indoor unit. An air conditioner includes an indoor unit 8 having at least one inlet 6 and one outlet 8; a cross-flow fan 1 connected to a fan motor; a front heat exchanger 2; and a back heat exchanger 3, wherein an installation angle .alpha. of the front heat exchanger 2 positioned above the rotational center of the cross-flow fan 1 relative to the horizon is 65.degree..ltoreq..alpha..ltoreq.90.degree., a point of the back heat exchanger 3 closest to the front heat exchanger 2 is located adjacent to the front heat exchanger 2 from the rotational center of the cross-flow fan 1, and an outlet angle .beta.2 of a blade of the cross-flow fan 1 is 22.degree..ltoreq..beta.2.ltoreq.28.degree..