To provide an air cleaning filter which can remove dust and fine materials from the air flowing in an air conditioner, electronic equipment, etc., when the filter is attached to the outside of the air conditioner, equipment, etc., and does not require much maintenance work.

Many granular filter mediums composed of activated carbon, etc., are put between fabric-shaped fibrous materials, such as nonwoven fabrics, etc., and the fibrous materials are housed in cases 1 having air flowing-through sections, such as slits, etc. Then the cases 1 are fixed to the outside of the air intakes of the indoor machine 6, etc., of an air conditioner. The fabric-shaped fibrous materials can be used as filters even when the materials are not housed in the cases 1. Alternatively, a mat-like filter medium obtained by gathering fibers adhered with a filter medium in a mat-like shape can also be used. Such a filter is attached to the outside of an air conditioner, etc., separately from the internal filter of the air conditioner, etc. Since the filter is attached to the outside of equipment, the filter has such versatility that the filter can be used regardless of the kind of the equipment. Depending not only upon the fibrous material, but also upon the filter medium, the filter can remove bad smells and such a very small object as the tick, etc. The soiling state of the filter can be discriminated at a glance and the filter can be provided at a low cost. In addition, the labor of the maintenance work of the filter can be reduced.