A fan control method of an air purifier includes: an operating mode determining process of determining an operating strength of the air purifier; a first fan motor driving process of operating a first fan motor at a first operating speed corresponding to the operating strength, such that a fan coupled to the first fan motor is rotated; and a second fan motor driving process of operating a second fan motor at a second operating speed altered from the first operating speed by a preset value, such that a fan coupled to the second fan motor is rotated.
