Iron containing a high amount of chromium is known to be inferior to ductility due to σ phase formation so that it is generally difficult to apply the plastic deformation process although the alloy possesses a superior characteristics of an excellent corrosion resistance. In this study, Fe-50mass%Cr alloy was melted using high purity powder and the deformation behavior has been investigated by cold rolling and tensile test. The tensile test yielded that the alloy revealed a serration at an early stage of tensile deformation and then the serrated flow vanished to change to a normal work hardening flow at the later stage. The former was governed by twin formation process, the latter by dislocation multiplication one, bringing about a high ductility of 20% or over. The reduction ratio in cold rolling was attained as high as 90%, thus the high corrosion-resistant alloy is able to possess a high ductility.