A filter material take-up product and a paper winding core, which are free from secondary-contaminattion by an outgas while being transported or stocked. Irrespective of its application such as building air conditioner, an air cleaner or a semi-conductor factory, the amount of the outgas to be generated from the filter take-up product for the air filter can be kept at a negligible level. The filter take-up product for the air filter is produced by coating and wrapping the filter material for the air filter, as wound on the winding core, with a film wrapping material which is so made of phenolic compounds, carboxylate esters, phosphate ester or cyclic siloxance as to have an outgas generation in an amount of 100 ng/g or less by the dynamic head space method.