An air cleaner is provided. The air cleaner may include a first air cleaning module including a first fan, a first filter, and a first inlet through which air is suctioned in a radial into the first filter; a second air cleaning module provided over the first air cleaner including a second fan, a second filter, and a second inlet through which air is suctioned in the radial direction to the second filter; and an air flow controller coupled with the second air cleaning module and including a third fan to control a flow of the air discharged from the second air cleaning module.