NOVELTY - A resin material comprises thermoplastic resin (A) and polymer (B). The polymer (B) is a graft copolymer obtained by multistage polymerization of monomer mixture containing ring structure-containing methacrylic monomer (I) and (meth)acrylic acid and/or its salt.    USE - Resin material is used for forming molded product e.g. film e.g. optical film (all claimed). Uses include but are not limited to interior and exterior cladding material for motor vehicle, personal computer, portable devices and solar cell, solar cell back sheet, camera, Fresnel lens, liquid crystal displays, fiber optic connector, motor vehicle headlight, tail-lamp lens, road sign, bathroom fitments, etc.    ADVANTAGE - The resin material provides molded product having high transparency, excellent thermal stability, solvent resistance, mechanical strength, surface external appearance, flexibility, crack resistance and optical homogeneity, and reduced foreign material and defects.    DETAILED DESCRIPTION - A resin material comprises thermoplastic resin (A) and polymer (B). The polymer (B) is a graft copolymer obtained by multistage polymerization of monomer mixture containing ring structure-containing methacrylic monomer of formula (I) and (meth)acrylic acid and/or its salt.    R9=H, or optionally substituted linear or branched 1-12C alkyl;    R10=1-24C aryl having isocyclic ring structure or heterocyclyl ring structure, or 1-24C alicyclic group (both optionally substituted);    l=1-4;    m=0-1;and    n=0-10.    INDEPENDENT CLAIMS are included for the following:    (1) film, which is obtained by molding the resin material by melt-extrusion method;    (2) pellets, which are obtained by heat-melting the resin material;    (3) multilayer structure-containing graft copolymer, which has crosslinked polymer layer (B1) and layer (B2) formed by polymerizing ring structure-containing methacrylic monomer (I) and monomer mixture containing (meth)acrylic acid and/or its salt; and    (4) molded product, which contains thermoplastic resin, and multilayer structure-containing graft copolymer having a monomer structural unit (I) and a polymer layer containing glutaric anhydride structural unit.