A ferromagnetic object, located in the Earth’s magnetic field, changes its distribution. Through measuring such disturbances, one can locate the object and destroy it. To conceal the object, a special winding is placed inside its ferromagnetic shell, and its task is to eliminate the disturbances in the distribution of the Earth’s magnetic field. A thin walled elliptical shell, made of ferromagnetic material, is examined as the object model. There are coils, placed inside the shell, and their task is to generate a magnetic field, which is eliminating the effect, the shell is making on the distribution of the Earth’s magnetic field in the surrounding area. Such a procedure is called magnetic masking and the winding used for this purpose is called the masking winding. The possibility of building the masking windings for the ferromagnetic elliptical shell, situated in a transverse magnetic field respectively to its major axis, is also examined. The solution of Maxwell’s equations, which are describing the magnetic field distribution caused by the ferromagnetic shell presence in the Earth’s magnetic field, is found. Furthermore, the ability of selecting coils, which are eliminating the perturbations of the magnetic field outside the shell completely, is proven.