The invention provides a resin composition whose dyeability is improved. The composition comprises a resin, and a hydrotalcite type material in an amount of 0.1 to 30 parts relative to 100 parts of the resin, wherein the hydrotalcite type material is represented by formula (1): (M2+)1-x(M3+)x(OH)2(A−)x.mH2O  (1) wherein M2+ is at least one species of divalent metal ions, M3+ is at least one species of trivalent metal ions, A− is at least one species of alkylbenzenesulfonic acid ions with the alkyl group having at least 8 carbon atoms, x is the number satisfying the inequality: 0