A filter reinforcing material is disclosed that does not cause peeling or pleat adhesion at the time of pleating, is excellent in pleating, and has high stiffness. A filter reinforcing material includes a bonding layer comprising a thermal bonded nonwoven including thermal bondable short fibers, and a reinforcing layer comprising a nonwoven including high-melting fibers having a higher melting point than a melting point of the thermal bondable short fibers having the lowest melting point in the bonding layer by 30° C. or more. Further, the bonding layer preferably comprises two or more kinds of thermal bondable short fibers with a fineness difference of more than or equal to 5 dtex.