Provided is alloy for medical use and a medical device that is novel and useful. The alloy for medical use according to, for example, an embodiment of the present invention is mainly composed of three kinds of elements, namely gold (Au), platinum (Pt), and niobium (Nb). A total content of the three kinds of elements can be no smaller than 99% by weight, in which a platinum content can be no smaller than 5% by weight and no greater than 50% by weight and a niobium content can be no smaller than 3% by weight and no greater than 15% by weight. By adjusting the content ratio of the three elements, for example, it is possible to reduce or prevent artifacts in MRI. Non-magnetization is also possible.