To provide a no-crimp short-cut fiber of a flame-retardant polyester, having flame retardancy and good dispersibility.

This no-crimp short-cut fiber of the flam-retardant polyester is formed out of a polyester which is obtained by copolymerizing a phosphorus compound in an amount of 2-10 mol%, wherein the fiber has a single fiber fineness of 0.5-1.5 dtex and a fiber length of 1-15 mm, and a metal alkylphosphate-based finish is applied in an amount of 0.01-0.1 mass% to surfaces of the fiber.