An air-conditioning apparatus for an electric vehicle, which includes a main core disposed on a ventilation channel, and a thermoelectric device having a first surface and a second surface performing heat generation or heat absorption. An air-conditioning channel through which cooling water circulates around the first surface of the thermoelectric device and the main core is also provided along with a waste heat channel through which the cooling water circulates around the second surface of the thermoelectric device and an electric component A controller configured to control the thermoelectric device so that the first surface and the second surface serve as a heat generating surface and a heat absorbing surface, respectively, and control circulation through the air-conditioning channel or the waste heat channel in a heating mode.