An alloy wire made of a material selected from one of a group consisting of a silver-gold alloy, a silver-palladium alloy and a silver-gold-palladium alloy is provided. The alloy wire is with a polycrystalline structure of a face-centered cubic lattice and includes a plurality of grains. A central part of the alloy wire includes slender grains or equi-axial grains, and the other parts of the alloy wire consist of equi-axial grains. A quantity of the grains having annealing twins was 20 percent or more of the total quantity of the grains of the alloy wire.