Abstract: Disclosed is a thermoplastic resin composition comprising (A) an amorphous resin and further comprising, per 100 parts by weight of the amorphous resin,0.01 to 20 parts by weight of (B) an epoxy group-containing ethylene copolymer, and0.01 to 20 parts by weight of at least one member selected from the group consisting of (C) a polyfunctional compound and (D) a carboxylic acid metal salt, wherein the polyfunctional compound contains, per molecule, at least two identical or different functional groups selected from the group consisting of carboxyl group, amino group, carboxylic acid anhydride group and a unit represented by the formula (1) ##STR1## wherein X and Y are identical and each represents oxygen atom or sulfur atom, or one of X and Y is an oxygen atom and the other is a sulfur atom, or wherein the polyfunctional compound contains, per molecule, at least one unit represented by the formula (2) ##STR2## wherein Z represents oxygen atom or sulfur atom.