The present invention provides a flame-retardant resin composition comprising 100 parts by weight of a bromine-containing copolymer composition containing 1 to 40% by weight of bromine, and comprising 0 to 30 parts by weight of a flame-retarding adjuvant and 0.5 to 30 parts by weight of a polyorganosiloxane-reinforced resin component obtained by polymerizing a vinyl monomer (d) in the presence of a polyorganosiloxane polymer. The flame-retardant resin composition of the present invention has attained a remarkably higher flame retardancy by the inclusion of a polyorganosiloxane-reinforced resin. A significant improvement in the dripping phenomenon has also been achieved. Further, this composition exhibits superior impact resistance and moldability, and a superior outer appearance in the formed products.