The present invention relates to an artificial vascular graft having ultra fine fibers smaller than 0.5 denier in fineness as part of the inner wall. The artificial vascular graft of this invention is very flexible and produces very low blood leakage. The ease of performing anastomoses is greatly improved. Because of the ultra fine fiber there are many sites to which live cells adhere, the adaptability of the live cells to the fibers of the vascular graft increases, an excellent antithrombotic effect is exerted by the vascular graft, and the formation of the endothelial cells is satisfactory and is observed at a very early stage.