An endless metallic belt formed of a nickel alloy which contains at least one element selected from the first group of elements consisting of phosphorus, boron, silicon, germanium, selenium, antimony, tellurium, bismuth and astatine, and, in an X-ray diffraction pattern of which, half widths of X-ray diffraction peaks of the (111) crystal plane and (200) crystal plane are both from 0.5.degree. to 2.5.degree..