To provide a polyester fiber for sandbag, which provides a sandbag having a high strength, an excellent weather resistance and flexibility and hardly slidable even if used in a piled form.

The polyester fiber for sandbag includes a multifilament composed of a polyethylene terephthalate containing carbon black in the fiber in an amount of 0.2-1.2 mass%, having an elongation at break of 5.5 cN/dtex, and a ratio of fiber yarns to coefficient of static friction of the yarn (F/Fs) of 1.7.