An indoor air-conditioning unit, comprising a shell (1) and a heat exchanger (3) and a cross-flow fan (2) that are disposed in the shell (1). The cross-flow fan (2) comprises a cross-flow wind wheel (22) and a volute that are mutually matched. The volute comprises a top cover (21) and a volute tongue (23). A diffusion portion of the cross-flow fan (2) is formed between the top cover (21) and the volute tongue (23). The diffusion portion is downward and an air outlet is formed in a lower side surface of the shell (1). A rear side surface and/or an upper side surface of the shell (1) is provided with an air return port. An included angle λ of the connection lines of two end points of a molded line of the top cover (21) and the center of the cross-flow wind wheel (22) ranges from 185° to 225°.
