An air purifying system may include a main air purifier that has a flat upper surface configured to support at least two cylindrical portable air purifiers. Each of the main and portable air purifiers may have a fan to suction air and a filter to filter suctioned air. The upper surface of the main air purifier may include a seating groove, an elastic member provided in the seating groove, and a seating plate resting on top of the elastic member. When a portable air purifier is seated on the seating groove, the elastic member may be compressed and the seating plate may be lowered such that the portable air purifier may be supported within an inner wall of the seating groove. When the portable air purifier is removed from the seating groove, the elastic member may expand and raise the seating plate back to an initial position.