PURPOSE: To reduce the load of a blower motor by applying voltage across a plurality of conductive porous layers laminated by interposing permeable non-conductive layers in an air filter for an air cleaner for air conditioning or the like.

CONSTITUTION: Two conductive porous layers 1 or more are laminated by interposing air permeable non-conductive layers 2 composed of a non-woven cloth or the like used as a filter medium to constitute a filter. For the conductive porous layers 2, wet and dry non-woven cloth containing conductive fibers or the like is used mostly, although not particularly specified. A non-woven cloth sheet into which metallic fibers are contained is used for the purpose. Power source terminals 5 connected with cathodes or anodes of a power source are disposed respectively on the conductive porous layers 1, 1, connected with the power source and voltage is applied among the conductive porous layers 1, 1. Also folding work can be carried out to increase the filter area.