A magnetic memory 1 having a wire 5 extended in a direction of arbitrary decision, an electro-resistivity effect element 4 disposed adjacently to the wire 5, and a counterelement side yoke 20B disposed adjacently on the side opposite the magneto-resistivity effect element 4 in the wire 5 and having the thickness of the counterelement side yoke 20B so set as to be larger than 50 nm and smaller than 150 nm. Owing to conformity with this invention, this magnetic memory is enabled to homogenize the magnetization property during the course of writing operation and perform the writing work with a low electric current.