Abstract: An air conditioner indoor unit has a box-shaped body casing 1. A pair of air inlet ports 5 are formed in a front surface of the body casing 1. A pair of air outlet ports 7 are formed on both sides of each of the air inlet ports 5. A pair of air passages 6 are each formed in the body casing 1 and extend from the corresponding air inlet port 5 toward the air outlet ports 7. Turbofans 8 are arranged in the body casing 1 in correspondence with the air inlet ports 5. A pair of heat exchangers 9 are arranged on both sides of each of the turbofans 8 in correspondence with the associated two air outlet ports 7. A drain pan 15 is arranged below the heat exchangers 9 and the turbofans 8. Refrigerant pipes 21a, 21b, 21c, 21d, which connect the heat exchangers 9 to each other, are received in the drain pan 15.