Disclosed is a filter device, including: a filter cage, a filter cartridge sleeved at outer side of the filter cage and an end cap connected to one end of the filter cartridge; the end cap is provided with a through end hole, and one end of the filter cage corresponding to the end cap is provided with a middle column penetrating through the end hole; and the filter device further includes: a cover body installed at outer side of the end cap; where the end cap is provided with a plurality of clamping elements used for pressing against the middle column, and the cover body pushes the clamping elements to move to the middle column in a process that the cover body rotates around the middle column along a rotation direction, so that the middle column is clamped by the plurality of clamping elements.