In previous works, supersaturated magnetostrictive Fe-Al alloys were prepared by ion plating (IP) process. Ion-plating process is expected to form supersaturated solid solution of Fe-In of immiscible system in equilibrium thin film. In this study, Fe-III B supersaturated thin films were prepared by ion plating process of the dual vapor source and magnetostrictive characteristics of thin films were discussed. IP system was used for film preparation. Dense plasma flux (∼2.5 A) of source material can be dosed and deposited on a substrate. The flux of the source vapor is ionized by thermal electrons accelerated from molten pool to an electrode called “probe”. All sample films showed bcc structure. This may be caused by non-equilibrium condition as plasma-solid quenching peculiar of the IP. The sample of Fe-17 at%Ga and Fe-1.5 at%In showed maximum value of magnetostriction is about 200 ppm and 80 ppm at 1200 kA/m, respectively. [DOI: 10.1380/ejssnt.2009.801]