To obtain a binder for a nonwoven fabric, comprising an aqueous emulsion, a thermosetting amino resin and an aqueous solution of an acrylamide- based polymer, capable of suppressing the deterioration of tensile strength while hot, increasing the tensile strength and tear strength in an ordinary state, excellent in flexibility and useful for waterproofing, etc., of buildings.

This binder for a nonwoven fabric comprises (A) an aqueous emulsion, prepared by carrying out the emulsion copolymerization of 1-30 pts.wt. ethylenically unsaturated monomer containing amide group (e.g. acrylamide) with 99-70wt.% other ethylenically unsaturated monomers such as methyl acrylate and having 50-90°C glass transition temperature, (B) a thermosetting amino resin such as a urea resin and (C) an aqueous solution of an acrylamide- based polymer. The blending ratio of the components (A), (B) and (C) is respectively preferably within the range of (3-96)/(96-3)/(1-10) pts.wt. based on 100 pts.wt. sum total of the solid content of the components (A), (B) and (C).