An object of the present invention is to provide a thermoplastic resin composition capable of improving impact resistance and surface gloss of a molded article, and a molded article thereof. A thermoplastic resin composition of the present invention is comprising 100 parts by weight of a thermoplastic resin (a) and 0.5 to 30 parts by weight of a core-shell polymer composition (b), wherein the core-shell polymer composition (b) is obtained by polymerizing the shell-constituting components in the presence of a core obtained by polymerizing a monomer mixture (100% by weight in total) of 70% to 99.95% by weight of an alkyl acrylate having an alkyl group of 2 to 18 carbon atoms, 0.05% to 10% by weight of a polyfunctional monomer, and 0% to 20% by weight of a monomer copolymerizable with the alkyl acrylate and the polyfunctional monomer, and the polyfunctional monomers contains at least a compound having a plurality of same radically polymerizable functional groups in the molecule thereof.