An air conditioner for a vehicle which can block air introduced through a gap between an evaporator and an air-conditioning case and prevent condensate from overflowing toward a temperature adjusting door when condensate exceeding a drainable amount is generated. The air-conditioning case has an air passageway therein. An evaporator is disposed in the air passageway. A drain hole is disposed at a downstream side of the evaporator in an air flow direction to discharge condensate to the outside. A first baffle protrudes upwardly from a bottom surface of the air-conditioning case for preventing air from leaking between the air-conditioning case and the evaporator.