A magnetic functional device allowing magnetization switching at a high speed even if the size of a magnetic substance is made finer on the sub-micron order. The magnetic functional device includes an information carrier layer formed by a magnetic substance; and a strain-imparting layer (such as piezoelectric layer) formed below the information layer and operably configured to impart a drive force to change the direction of a magnetization vector lying in a first plane of the information carrier thereby processing binary or more information by magnetization directions of the information carrier layer; wherein the drive force is applied in pulse to the information carrier layer in a direction nearly perpendicular to the first plane in which lies the magnetization vector of the information carrier layer when the magnetization vector is in an initial state before the application of the drive force. An effective field derived from a magnetic anisotropy or exchange interaction is used as the drive force.