An air-conditioning apparatus for a vehicle, which includes an evaporator core and a heater core disposed on a ventilation channel overlapping each other, and thermoelectric device having a heat generating surface and a heat absorbing surface. A cooling line including a first cooling channel through which cooling water circulates around the heat absorbing surface and the evaporator core and a second cooling channel through which the cooling water circulates around the heat absorbing surface and an engine, and a heating line including a first heating channel through which the cooling water circulates around the heat generating surface and the heater core and a second heating channel through which the cooling water circulates around the engine and the heater core are also included. A controller controls concurrent circulation through the second cooling channel and the first heating channel or circulation through the second heating channel in a heating mode.