An air cleaner includes an ion generator arranged in a path from an inlet port to an outlet port, a humidifying filter arranged in the path at a position closer to the inlet port than the ion generator, a dust sensor and an odor sensor for detecting impureness of air, and a temperature sensor and a humidity sensor. When impureness is detected by the dust sensor and the odor sensor and when the temperature and the humidity attain a specific state (YES at S06 to S08), a fan motor is driven such that water is supplied to the ion generator in an amount larger than when the specific state is not attained (S14).
