To provide a vibration-suppression/base-isolation damper device which has such low temperature toughness as to be usable even in a cold district, absorbs vibration energy acting on a building structure or the like by earthquake or the like, and also can quickly converge the vibration.

A steel containing, by weight, 0.001 to 0.10% carbon, 0.1 to 3.0% silicon, 5.0 to <18.0% manganese, 0.01 to 20.0% chromium and 0.001 to 0.1% aluminum, and the balance iron is melted so as to have a chemical composition satisfying the conditions in which stacking fault energy SFE(mJ/m2) is ≤20 and, by a production method satisfying prescribed heat treatment conditions, cooling conditions and cold working conditions, a -Ms phase reaches 10 to 50 vol.%.