PURPOSE: A highly transparent thermoplastic resin composition consisting of a specific ABS resin and methyl methacrylate-acrylonitrile copolymer without deteriorating impact resistance.

CONSTITUTION: A thermoplastic resin composition, obtained by melt incorporating (A) an ABS resin, prepared by emulsion graft polymerizing 22W35wt% acrylonitrile, 65W78wt% styrene and 0W20wt% α-methylstyrene in the presence of polybutadiene or a diene based rubber latex containing ≥85wt% butadiene, and having 10W40wt% graft ratio with (B) a copolymer consisting of 80W99wt% methyl methacrylate, 1W20wt% acrylonitrile and 0W10wt% another copolymerizable monomer, preferably methyl acrylate, and having 5W30wt% content of acetone-insoluble matter, 3W10cP viscosity of a 10% solution of the acetone- soluble matter in methyl ethyl ketone and refractive index (a) of the acetone- insoluble matter and refractive index (b) of acetone-soluble matter satisfying the formula.