The present invention provides a flame retardant resin composition
comprising the following component (A), component (B), component (C) and
component (D), in which 0.1 to 50 parts by mass of the component (B),
0.001 to 30 parts by mass of the component (C) and 0.1 to 50 parts by
mass of the component (D) are blended with 100 parts by mass of the
component (A). Component (A): A rubber-modified styrene resin obtained by
(co)polymerizing an aromatic vinyl compound or an aromatic vinyl compound
and another vinyl monomer copolymerizable with the aromatic vinyl
compound in a presence of a rubber-like polymer; Component (B): A
thermally expandable graphite; Component (C): A layered clay material
modified by a water-soluble polymer; and Component (D): At least one
selected from the group consisting of silicone compounds, boron oxides,
aminotriazine sulfate compounds and aminotriazine compounds. The resin
composition is excellent in flame retardance and impact resistance.