Flame-retardant polyamide composition

A flame-retardant polyamide composition having a melting point of 280-340° C., comprising:

• 20-80 mass % polyamide resin (A) having a repeating unit composed of a multifunctional carboxylic acid unit (a-1) and a multifunctional amine unit (a-2) having 4-25 carbon atoms, the multifunctional carboxylic acid unit (a-1) composed of 30-100 mol % terephthalic acid unit, 0-70 mol % multifunctional aromatic carboxylic acid unit other than terephthalic acid, and 0-70 mol % multifunctional aliphatic carboxylic acid unit having 4-20 carbon atoms;
• 1-40 mass % flame retardant (B) composed of two or more compounds with different melt flow rates (MFR), and containing flame retardant (B1) having a MFR of 300-1,000 g/10 min and flame retardant (B2) having a MFR of 0.05-10 g/10 min, as measured at 270° C. under a load of 1,200 g;
• 5-60 mass % glass fiber (C), an aspect ratio of a cross section of which being larger than 3 and 10 or less;
• and
• 0.5-5 mass % auxiliary flame retardant (D) (where total amount of (A), (B), (C) and (D) is 100 mass %), wherein
• a warpage amount after reflow is less than 2 mm, the warpage amount measured by a method comprising:
• preparing as a test piece an injection molding article having a length of 50 mm, width of 30 mm and thickness of 0.6 mm;
• allowing the test piece to stand at 23° C. for 24 hours;
• measuring the difference X between maximum height and minimum height of the test piece placed on a flat plate;
• passing the test piece though a reflow furnace heated to 260° C. and cooling the test piece to 23° C.;
• measuring the difference Y between maximum height and minimum height of the test piece placed on a flat plate;
• and
• subtracting X from Y to find the warpage amount.