An indoor unit includes a heat exchanger provided on the downstream side of a fan and formed with a plurality of lower end portions in a vertical cross section from the front side to the back side of a casing, a plurality of drain pans provided below the lower end portions of the heat exchanger and configured to collect drain water occurring on the heat exchanger, and a drain channel provided between the drain pans and configured to be a flow channel of the drain, and a connecting port to which a drain hose configured to drain the drain water collected by the drain pans to the outside of the casing, and one of the drain pans is arranged to a level equal to or higher than the level of the other drain pan, and the drain channel is provided on the drain pan arranged on the back side of the casing.