Abstract: An object of this invention is to provide a solder material capable of, when joining an electronic component to a substrate with the solder material, improving heat fatigue resistance thereof and reducing damage of Ni film interposed therebetween. A solution of this invention is to assemble an electronic part by soldering a semiconductor device with a substrate using solder balls made of a solder material containing from 0.01 to 4.99% by weight of Fe; from 0.01 to 4.99% by weight of Ni, total thereof being from 0.02 to 5.0% by weight; from 0.1 to 8.0% by weight of at least one of Ag and In; from 0 to 70% by weight of Pb, balance containing Sn and unavoidable impurity.