A condensate water guide unit of an air conditioner for vehicles which collects and drains condensate water, generated on the evaporator, outside the air conditioner is disclosed. The condensate water guide unit includes a plurality of guide pieces for draining condensate water outside the air conditioner, and a support bar, which connects the guide pieces to each other. The guide pieces are in close contact with the lower end of an evaporator. Each guide piece has a guide slot for drawing condensate water formed on the surface of the evaporator, and a water moving passage for draining the drawn condensate water outside the air conditioner.