To improve the thermal stability of a brominated polymer type flame retardant in a flame-retardant resin composition containing a styrene-based resin and the brominated polymer type flame retardant to provide a flame-retardant resin molded article in which occurrences of black foreign substances and discoloration decrease. The flame-retardant resin composition contains 0.8 to 15 parts by mass of a halogen capture agent, 0.8 to 7 parts by mass of an antioxidant, and 0.8 to 6 parts by mass of liquid paraffin based on a total of 100 parts by mass of a styrene-based resin and brominated polymer type flame retardant, and a content of bromine is 18 to 42% by mass.