An air conditioner including a sensor kit. The air conditioner includes: a cabinet including a first side having a first through hole and a second side having a second through hole; a pipe formed to pass through the first through hole; a sensor kit provided on the second side; and a controller to be electrically connected to the sensor kit, wherein the sensor kit includes: a sensor configured to sense a pollution level of outside air; and a cover formed to cover the second through hole on the second side, and fixing the sensor.