To provide a flame retardant polyamide-based resin composition without containing a chlorine compound and bromine compound, and capable of highly balancing mechanical characteristics, processability, workability and flame retardance.

This flame retardant polyamide-based resin composition comprises based on (A) 100 pts.mass of a polyamide-based resin, (B) 5 to 70 pts.mass of an at least one kind selected from a phosphazene compound and phosphinic acid salt, and (C) 1 pt.mass to 20 pts.mass of a polycarbonate-based resin.