To keep pressure loss and collection efficiency to be held originally of a filter material and to maintain long-term antibacterial power at a relatively low cost.

The filter material for an air filter is obtained by applying an antibacterial component-containing water soluble resin and/or an antibacterial component-containing water dispersible resin to the filter material for air filter as a binder for imparting antibacterial properties and sheet strength. In this case, an antibacterial component contains a water-soluble complex wherein silver ions are coordinated with a thiol group-containing compd. or a hardly water-soluble complex wherein silver ions are coordinated with a thiol group- containing compd. and a water-soluble amine.