To provide an apparatus for severe plastic deformation and a severe plastic deformation method which can effectively introduce high distortion to a metal material and which are industrially practical.

The metal material is caliber-rolled over a plurality of times by successively using a plurality of calibers having opening shapes different from each other. At that time, the plurality of calibers are constituted so that each of opening areas is equal to the cross-sectional area of the metal material of a base stock and, by designing the mode of transition of the opening shapes of the plurality of calibers so that the screw-down direction to the metal material is changed for each of a plurality of caliber rolling steps, large plastic distortion is uniformly imparted to the metal material while remarkably reducing deformation force.