A flame-retardant glass fiber-reinforced polyamide resin composition, containing: 100 parts by mass of a flame-retardant resin composition consisting of (A) 60 to 90 percent by mass of a polyamide resin, and (B) 40 to 10 percent by mass of a flame retardant containing no halogen atom, (A)+(B) being 100 percent by mass; and 60 to 210 parts by mass of a flattened glass fiber (C) having a flat section of 1.5-10 in a ratio of major axis/minor axis, wherein the polyamide resin (A) contains a crystalline polyamide resin (a1) and an amorphous polyamide resin (a2), the flame retardant containing no halogen atom (B) contains a phosphinate (b1) and/or a diphosphinate (b2), and a blending ratio of the amorphous polyamide resin (a2) in the polyamide resin (A) is 0.1≦(a2)/(A)≦0.5.