The present invention relates to an alloy for medical use, including Pt, Co, Cr, Ni, and Mo. The alloy includes 10 atom % or more and 30 atom % or less of Pt, 20 atom % or more and 31 atom % or less of Cr, 5 atom % or more and 24 atom % or less of Ni, 4 atom % or more and 8 atom % or less of Mo, the balance Co, and unavoidable impurities, and a ratio of the Ni content (CNi) to the Pt content (CPt), CNi/CPt is 1.5 or less. The present invention can be applied to various kinds of devices for medical use, such as catheter, embolic coils, and guide wires, in addition to stents such as flow-diverter stents.