PURPOSE: To produce a filter paper for air filter having proliferation suppressing effect both on fungi and bacteria. CONSTITUTION: This filter paper for air filter containing 0.1-0.5wt.% (based on the filter paper) of a thiabendazole agent is produced by the mixed paper- making, by mixing 5-20wt.% (based on the filter paper) of glass fibers containing 0.3wt.% of univalent Ag ion and having fiber diameter of 0.6-9μm. Proliferation suppressing effect on both W fungi and bacteria can be achieved by the use of the filter paper incorporated with a thiabendazole-type compound acting on the respiratory system of fungi and glass fibers containing Ag ion effective against bacteria.
