The reinforced thermoplastic resin composition of the present invention includes: 50 to 90% by weight of a polycarbonate resin (A); 10 to 50% by weight of a graft copolymer mixture (B) (provided that a total amount of the component (A) and the component (B) accounts for 100% by weight) which is obtained by graft-polymerizing an aromatic alkenyl compound monomer unit (a) and a vinyl cyanide compound monomer unit (b) onto a rubber polymer (B1); and 6 to 22 parts by weight of an inorganic filler (D) which has been surface-treated with a water-soluble polyamide, relative to the total of 100 parts by weight of the polycarbonate resin (A) and the graft copolymer mixture (B). There is provided a reinforced thermoplastic resin composition exhibiting excellent moldability, generates a minimal amount of gas during molding, and also being capable of improving the rigidity of the resulting molded article and the impact resistance when dropping the product.