To form a weak magnetic part by carrying out heating treatment at a temperature lower than that in the case of a material for the conventional member, as a material for a composite magnetic member by which both magnetic properties of ferromagnetism and weak magnetism can be attained with a single composition.

The material is that for a composite magnetic member having a ferromagnetic part and a weak magnetic part with a single composition. The material has a composition consisting of, by mass, ≤0.10% C, 0.10 to 2.0% Si, 0.10 to 4.0% Mn, >20.0% to <28.0% Ni and the balance essentially Fe and also has a martensitic structure, and further, the amount of spontaneous magnetization (J) under the external magnetic field of 1 T(tesla) is made to ≥1.3 T.