The present invention relates to a medical Pt—W alloy, containing 10 mass % or more and 15 mass % or less of W, with the balance being Pt and inevitable impurities, in which a Zr content is 1000 ppm or less. Limiting the Zr content can improve workability, particularly workability at the stage of hot working. Regarding impurity control, further limiting a Ca content to 250 ppm or less can provide more suitable workability. The present invention is good in workability in processing into a wire included in an embolic coil, a guide wire or the like.