PURPOSE: To prevent washer smell from intruding in the room of a vehicle by moving an inside-outside air switching damper to the position for guiding air in the room of vehicle by a time corresponding to a specified period when the smell of washer is judged to intrude in the room and air outside the room is guided in an air introduction passage.

CONSTITUTION: A device for preventing washer smell into the room of vehicle 10 is mounted on an air conditioner for a vehicle having an inside-outside air switching damper 50 for guiding air inside the room and air outside the room selectively to an air introducing passage 48 and an actuator for moving the dumper 50. In this case, to a control circuit 34 of the device 10 are connected a position sensor 56 for detecting the position of inside-outside air switching dumper 50 and a window washer switch 38 of a window washer 26. When the smell of washer is judged to intrude in the room and air outside the room is introduced in the air introduction passage 48, the actuator 54 is controlled to introduce air inside the room by a time corresponding to a specified period.