Provided are a thermoplastic resin composition and a molded product using same, wherein the thermoplastic resin composition includes a base resin including (A-1) 10 wt % to 30 wt % of a first acrylate-based graft copolymer having an acrylate-based rubbery polymer with an average particle diameter of 300 nm to 400 nm; (A-2) 10 wt % to 35 wt % of a second acrylate-based graft copolymer having an acrylate-based rubbery polymer with an average particle diameter of 100 nm to 200 nm; (B) 10 wt % to 15 wt % of an aromatic vinyl compound-vinyl cyanide compound copolymer; and (C) 35 wt % to 55 wt % of α-methylstyrene-based copolymer, and (D) 1 to 5 parts by weight of an ultrahigh molecular weight styrene-acrylonitrile copolymer having a weight average molecular weight of greater than or equal to 5,000,000 g/mol, based on 100 parts by weight of the base resin.