A medical Au-Pt-Pd alloy consisting of Au, Pt, and Pd, a total amount of 0 mass% or more and 0.5 mass% or less of Ca and Zr as optional additive elements, and inevitable impurities, wherein the medical Au-Pt-Pd alloy has an alloy composition inside a polygon (A1-A2-A3-A4) surrounded by straight lines connected at point A1 (Au: 53 atom%, Pt: 4 atom%, and Pd: 43 atom%), point A2 (Au: 70 atom%, Pt: 4 atom%, and Pd: 26 atom%), point A3 (Au: 69.9 atom%, Pt: 30 atom%, and Pd: 0.1 atom%), and point A4 (Au: 49.9 atom%, Pt: 50 atom%, and Pd: 0.1 atom%) in a Au-Pt-Pd ternary state diagram, the medical Au-Pt-Pd alloy comprises a total amount of 0 ppm or more and 200 ppm or less of Ag, Co, Cr, Fe, Ir, Mg, Ni, Rh, Ru, Si, Sn, and Ti as inevitable impurities, and the additive elements and inevitable impurity elements replace a part of Au in the Au-Pt-Pd alloy, characterized in that in a metal structure on any cross-section, with a composition of a mother phase Au-Pt-Pd alloy as a criterion, at least one of a Au-rich phase which is an alloy phase having a Au content higher by 4 atom% or more than that of the mother phase and a Pt-rich phase which is an alloy phase having a Pt content higher by 4 atom% or more than that of the mother phase is distributed, and a total of an area ratio of the Au-rich phase and an area ratio of the Pt-rich phase is 1.5% or more and 25.4% or less, and the medical Au-Pt-Pd alloy has a volume magnetic susceptibility of -32 ppm or more and 60 ppm or less and a Young's modulus of 100 GPa or more, wherein the area ratio refers to one based on the observation visual field of a material structure on an arbitrary cross-section and is determined as described in the description, the volume magnetic susceptibility is determined with a magnetic balance as described in the description, and the Young's modulus is determined with a tensile tester as described in the description. the medical Au-Pt-Pd alloy has an alloy composition inside a polygon (A1-A2-A3-A4) surrounded by straight lines connected at point A1 (Au: 53 atom%, Pt: 4 atom%, and Pd: 43 atom%), point A2 (Au: 70 atom%, Pt: 4 atom%, and Pd: 26 atom%), point A3 (Au: 69.9 atom%, Pt: 30 atom%, and Pd: 0.1 atom%), and point A4 (Au: 49.9 atom%, Pt: 50 atom%, and Pd: 0.1 atom%) in a Au-Pt-Pd ternary state diagram, the medical Au-Pt-Pd alloy comprises a total amount of 0 ppm or more and 200 ppm or less of Ag, Co, Cr, Fe, Ir, Mg, Ni, Rh, Ru, Si, Sn, and Ti as inevitable impurities, and the additive elements and inevitable impurity elements replace a part of Au in the Au-Pt-Pd alloy, characterized in that in a metal structure on any cross-section, with a composition of a mother phase Au-Pt-Pd alloy as a criterion, at least one of a Au-rich phase which is an alloy phase having a Au content higher by 4 atom% or more than that of the mother phase and a Pt-rich phase which is an alloy phase having a Pt content higher by 4 atom% or more than that of the mother phase is distributed, and a total of an area ratio of the Au-rich phase and an area ratio of the Pt-rich phase is 1.5% or more and 25.4% or less, and the medical Au-Pt-Pd alloy has a volume magnetic susceptibility of -32 ppm or more and 60 ppm or less and a Young's modulus of 100 GPa or more, wherein the area ratio refers to one based on the observation visual field of a material structure on an arbitrary cross-section and is determined as described in the description, the volume magnetic susceptibility is determined with a magnetic balance as described in the description, and the Young's modulus is determined with a tensile tester as described in the description.