An Au bonding wire for semiconductor device, comprising a wire-shaped Au alloy material consisting of: 3-15 mass ppm of Be, 3-40 mass ppm of Ca, 3-20 mass ppm of La, 3-20 mass ppm of at least one functional element selected from the group of Ce, Eu, Mg, and Si, and the remainder of Au, wherein the diameter of said Au alloy bonding wire is less than 23 microns, wherein said bonding wire has improved roundness of compressed bonded ball and improved fracture stress.